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ENGINEERING  CHEMISTRY. 


M  Published  by  |^ 

The    Chemical    Publishing    Co.  | 

Easton,  Penna.  S 

Publishers  of  Scientific  Books  M 

Engineering  Chemistry  Portland  Cement  g 

Agricultural  Chemistry  Qualitative  Analysis  g 

Household  Chemistry  Chemists'  Pocket  Manual  g 

Metallurgy,  Etc.  g 


Engineering  Chemistry 


A  Manual  of  Quantitative  Chemical  Analysis  for  the 
Use  of  Students,  Chemists  and  Engineers. 


FIFTH  EDITION 


BY 


THOMAS  B.  STILLMAM,  M.Sc,  Ph.D. 

Late  Professor  of  Engineering  Chemistry  in  the  Stevens  Institute  of  Tech- 
nology.    Member  :  Societe  Chimique  de  France  ;  Deutsche  Chemische 
Gesellschaft,  Berlin;  American  Chemical  Society;  Internat- 
ional Society  for  Testing  Materials  for  Construction, 
Zurich  ;  American  Electro-Chemical  Society ; 
Society  of  Chemical  Industry, 
London. 


WITH  ONE  HUNDRED  AND  FIFTY  ILLUSTRATIONS 


EASTON.  PA. : 

THE  CHEMICAL  PUBLISHING  CO. 
1916 


LONDON,    ENGLAND  : 

WILLIAMS  &  NORGATE 

14    HENRIETTA    STREET,    COVENT    GARDEN,    W.    C. 


Copyright.  1895.  by  Edward  Hart 
Copyright,  1900.  by  Edward  Hart 
Copyright,  1905,  by  Edward  Hart 
Copyright,  1910,  by  Edward  Hart 
Copyright,   1916,  by  Edward  Hart 


PREFACE. 


"The  master  is  gone.     The  master's  tvork  is  here." 

As  this,  the  5th  edition  of  "Engineering  Chemistry,"  was  ap- 
proaching completion,  the  author,  Thomas  B.  Stillman,  Ph.D., 
died,  August  10,  191 5. 

That  the  final  completion  was  possible  is  due  to  the  hearty 
co-operation  and  earnest  work  of  many  good  friends  to  whom 
the  editors  extend  herewith  deepest  thanks — namely  to  Clarence 
Carr,  Captain  U.  S.  N.,  I^ewis  F.  Lyne,  Jr.,  Oil  Specialty  and 
Supply  Co.,  E.  G.  Bashore,  Chief  Chemist,  Babcock  and  Wilcox 
Company,  Professor  William  Main,  George  H.  Gibson,  Harrison 
Safety  Boiler  Works,  W.  H.  Fulweiler,  Chemist,  United  Gas 
Improvement  Co.,  R.  E.  Brueckner,  M.  E.,  R.  Vuilleumier,  Chief 
Engineer,  Pintsch  Compressing  Co.,  and  to  the  Kennecott  Lab- 
oratories. 

AlvBKRT  E.  STII^IvMAN,  E.  M.,  M.Sc, 
Thomas  B.  Stili^man,  M.  E., 

Editors. 

August  10,  19 16. 


^°\ 


CONTENTS. 


PAGE 

The  Examination  and  Analysis  of  Coal  and  Coke i 

The  Examination  and  Analysis  of  Limestone 65 

The  Examination  and  Analysis  of  Iron  Ores 71 

The  Analysis  of  Iron  Pyrites 78 

The  Commercial   Sampling  of  Iron   Ores 80 

The  Analysis  of  Blast  Furnace  Slacr 88 

The  Analysis  of  Manganese  Ores 90 

Methods  for  Copper,  Lead  and  Zinc 91 

Graphic  Method  for  Blast  Furnace  Charges 95 

The  Blast  Furnace  as  a  Power  Plant 98 

Cast    Iron    Analysis no 

Foundry    Chemistry    115 

The  Examination  and  Analysis  of  Steel 126 

Analysis  of  Tin  Plate 153 

Alloys 160 

The   Chemical   and   Physical    Examination   of   Portland   and   Natural 

Cements  195 

Concrete    242 

Analysis  of  Clay,  Kaolin,  Fire  Sand,  Building  Stones,  etc 250 

Asphalt 273 

Methods  of  Testing  Coal  Tar  and  Refined  Tars,  Oils  and  Pitches...   349 

The  Examination  of   Lubricating  Oils 362 

Remarks  on  Lubricants  and  Lubrication 421 

Oils  Used  for  Illumination 441 

Linseed  Oils    453 

Fuel  Oil    455 

Ultimate  Analysis  of  Oils 472 

Soap   Analysis    475 

The  Analysis  of  Paris  Green 494 

Paint  Analysis    496 

The  Chemical  and  Physical  Examination  of  Paper 544 

Water  Analysis    570 

Filtration  of  Water 600 

Water  for  Locomotive  Use 606  • 

Feed  Water  Heaters 611 

Fuel    Economizers     623 

Gas    Analysis 627 

Flue  Gas  Analysis 627 

Analysis  of  Illuminating  Gas 655 

Gas  Calorimetry   665 


CONTr:NTS  V 

PAGE 

Manufacture  of  Water  Gas 670 

Natural   Gas    677 

Acetylene    679 

Valuation  of  Coal   for  Gas  Production C90 

Manufacture  of  Oil  Gas C95 

Practical    Photometry    705 

Pyrometry    718 

Appendix 728 

Anah'sis  of  Cylinder  Deposits 728 

Analysis  of  Cyanides 729 

Analysis   of   Welsbach   Mantles ; 730 

Analysis  of  Gelatine  Dynamites 731 

Tables    732 

Determination   of    Phosphorus    Pentoxide 736 

Iron  Determinations   738 

Index 745 


LIST  OF  ILLUSTRATIONS. 


FIG.  PACK 

1.  Abbe  pulverizer   19 

2.  Emerson  calorimeter 35 

3.  Emerson  calorimeter   37 

4.  Ignition  cup 39 

4a.  Crucible  for  coke  analysis 55 

4b.  Coke  shatter  test  apparatus 64 

5.  Apparatus  for  limestone  analysis 67 

6.  Carbon  dioxide  apparatus 69 

7.  Bunsen  valve  stopper 71 

8.  Allen  apparatus  for  ferrous  oxide 74 

9.  Parallel  system  of  ore  sampling 80 

10.  Ziz  zag  system  of  ore  sampling 80 

11.  Rope  net  system  of  ore  sampling 81 

12.  Diagram  for  moisture  sampling 82 

13.  Cone  sampling  83 

14.  Face  sampling   84 

15.  Graphic  method  for  calculating  blast  furnace  charges 96 

16.  Apparatus  for  filtration  in  determination  of  carbon  by  the  direct 

combustion  method    131 

17.  Vanier  combustion  train 133 

18.  Colorimeter  135 

19.  Camp's   agitator    141 

20.  Apparatus  for  determination  of  sulphur  by  the  evolution  method  145 

21.  Method  of  sampling  tin  plate 155 

2.2,.     Le  Chatelier  specific  gravity  apparatus 210 

23.  Vicat  apparatus  213 

24.  Details  for  briquette 216 

25.  Details  for  gang  mold , 217 

26.  Mold  for  compression  test  pieces 217 

2.T.     Form  of  clip 220 

28.  Riehle  U.  S.  standard  1000-pound  automatic  cement  tester 221 

29.  Ball  bearing  block  for  testing  machine 122, 

30.  Apparatus  for  making  accelerated  test 225 

31.  Appearance  of  ball  for  different  consistencies  of  cement  paste..  230 

32.  Soundness  pat  showing  shrinkage   cracks 231 

33.  Soundness  pat  showing  disintegration  cracks 231 

34.  Soundness  pat  with  top  surface  flattened  for  determining  time 

of  setting  231 

35.  Correct  method  of  molding  cement  pat 232 

36.  Method  of  mounting  Gilmore  needles 233 

37.  Correct  method  of  filling  briquette  mold 234 

38.  Correct  method  of  troweling  surface  of  briquettes 234 

39.  Hydraulic  compression  machine  for  cement  and  concrete  testing  243 

40.  Curves  showing  relative  compressive  strength  of  concretes 244 

41.  Impact  test  on  oil  mixed  concrete ; 248 

42.  Riehle  U .   S.  standard  testing  machine 255 

43.  Tagliabue    freezing   apparatus 258 

44.  Standard,  automatic  transverse  brick  testing  machine 261 

45.  Standard   rattler    265 

46.  Three  gang  abrasion  cylinder 269 

47.  Olsen  standard  impact  tester 270 

48.  Sohmer  hydrometer   282 


I,IST   OF   ILI^USTRATIONS  Vll 


FIG.  PAGE 

49.  New  York  testing  laboratory  oven 284 

50.  Apparatus  for  determining  soluble  bitumen 286 

51.  Apparatus  for  determining  paraffine  scale 294 

52.  Penetrometer    296 

53.  Instrument  for  determining  the  consistency  of  road  binders....  300 

54.  Smith  ductility  machine,  electrically  driven 303 

55.  Smith  ductility  machine,  hand  -power 304 

56.  Dow   briquette   mold 307 

57.  N.  Y.  State  tester 312 

58.  Reeve  centrifuge  extractor 316 

59.  Recovery  apparatus    319 

60.  Dulin   rotarex    320 

61.  Sieve  shaker  321 

62.  Apparatus  for  water  in  tar 349 

63.  Melting  point  apparatus 351 

64.  Breaking  point   apparatus 352 

65.  Light   oil   distillation 353 

66.  Special  apparatus  for  heavy  oil  analysis 357 

67.  Tagliabue  hydrometer  364 

68.  Chart  for  oil  analysis  by  specific  gravities 365 

69.  Williams-Westphal    balance    366 

70.  Modified   Westphal  balance    367 

71.  Araeo  picnometer  of  Eichhorn 368 

^2.     Apparatus  for  cold  test  of  oils 370 

73.  Engler  viscosimeter 373 

74.  Saybolt  Standard  Universal  viscosimeter 375 

75.  Tagliabue's    improved   viscosimeter 376 

75a.  Doolittle  viscosimeter 379 

76.  Apparatus  for  determining  the  flashing  and  burning  points  of 

combustible  liquids,  Cleveland  cup 383 

TJ.     Pensky-Martens  tester    385 

78.  Separatory  funnel  for  oils 392 

79.  Apparatus  for  determining  congealing  point  of  fatty  acids  from 

oils    394 

80.  Apparatus  for  determining  congealing  point  of  fatty  acids  from 

oils 394 

81.  Apparatus  for  melting  points  of  fatty  acids  from  oils 395 

82.  Apparatus  for  melting  points  of  fatty  acids  from  oils 395 

83.  Graduated  tube   401 

84.  "Gray"  carbon  residue  flask 402 

85.  Machine  for  determining  coefficient  of  friction  of  oils 410 

86.  Martens'  lubricant   friction  machine 412 

87.  Wisconsin  testing  apparatus  for  oils 443 

88.  Tagliabue  open  tester  for  illuminating  oils 446 

89.  Tagliabue  closed  tester  for  illuminating  oils 446 

90.  The  Foster  automatic  oil  tester 446 

91.  The  Saybolt  electric  oil  tester 449 

92.  The  Stammer  colorimeter   452 

93.  Microphotograph — Linen  fiber  before  treatment 547 

94.  Microphotograph — Linen  fiber  after  treatment 547 

95.  Alicrophotograph — Poplar  wood  fiber 547 

96.  Microphotograph — Poplar  wood  fiber 547 

97.  Microphotograph — Spruce  wood  fiber 548 


Vlll  LIST   OF   ILLUSTRATIONS 


FIG.  PAGE 

98.  Microphotograph — Spruce  wood   fiber    (after  pulping) 548 

99,  Microphotograph— Cotton  fiber   548 

100.     Microphotograph— Coniferous  fiber   548 

lOi.     Wendler  machine  for  paper  testing 559 

102.  Apparatus  for  absorption  of  blotting  paper 564 

103.  Apparatus  for  testing  resistance  to  elongation 565 

104.  Water  evaporating  apparatus 575 

105.  Apparatus  for  ammonia  determination 591 

106.  Wolff's  colorimeter    592 

107.  Dervaux  water  purifier 601 

108.  Dervaux  water  purifier    601 

109.  Filter  press   603 

no.     Filter   press    604 

111.  Heater  and  filter  press 605 

112.  Kennicott  water  softening  plant 610 

113.  Goubert   closed    feed   water   heater 612 

114.  Cochrane  feed-water  heater 616 

115.  Oil  separator  and  drain 617 

116.  Cochrane  metering  heater 619 

117.  Green    fuel    economizer 624 

118.  Modified   Elliott   apparatus 628 

1 19.  Orsat   apparatus    632 

120.  Hankee  pipette    635 

121.  Improved  Hankee  pipette 635 

122.  Hahn   apparatus    636 

123.  Continuous  sample  method  for  gas 638 

124.  Heat  carried  away  by  chimney  gases — chart 650 

125.  Per  cent.  CO2  in  gas — chart 651 

126.  Complete  gas  analyzing  apparatus 655 

127.  Standard  U.  G.  I.  Hempel  burette 656 

128.  Double  absorption  cuprous  chloride  pipette 657 

129.  Tutwiler  and  Bond  hygrometer 658 

130.  Diagram  of  illuminating  gas  anabasis 661 

131.  Junkers'   gas  calorimeter 666 

132.  Junkers'   gas   calorimeter 667 

133.  Lowe  water  gas  apparatus 672 

134.  General  acetylene  generator   681 

135.  Automatic   acetylene   generator 682 

136.  Acetylene  buoy    687 

137.  Sun  valve   688 

138.  Newbigging's  gas  production  plant 692 

139.  Pintsch  gas  plant,  side  elevation 697 

140.  Pintsch  gas  plant,  ground  plan 698 

141.  Bunsen  photometer    707 

142.  Standard   bar   photometer 715 

143.  Harcourt  pentone  lamp  716 

144.  Candle-power  computer    717 

145.  Electrical  resistance  pyrometer 719 

146.  Heraeus  quartz  glass  thermometer 721 

147.  Le  Chatelier  electric  pyrometer ^2.'>i 

148.  Indicating  and  recording  unit — Bristol  pyrometer 724 

149.  Fery  radiation  pyrometer 725 

A.     Bunsen  valve    74i 


ENGINEERING  CHEMISTRY. 


THE  PROXIMATE  ANALYSIS  OF  COAL  AND  COKE. 


Determination  of  Moisture,  Volatile  and  Combustible  Matter, 
Fixed  Carbon,  Ash,  and  Sulphur. 

Take  a  weighed  platinum  crucible  (capacity  about  25  cc.)  and 
weigh  in  it  1.5  grams  of  the  powdered  coal.  Transfer  to  a  dry- 
ing oven  and  heat  to  103°  C.  for  40  minutes;  cool  in  a  desic- 
cator/ and  weigh.     Loss  is  moisture. 

Grams 

Crucible  -|-  cover  -f  coal 26. 1 1 7 

Crucible  +  cover   24.617 


Coal   taken 1500 

Crucible  -j-  cover  +  coal,  before  drying 26.117 

Crucible  +  cover  ~|-  coal,  after  drying 26.109 


-o 


2  " 


Moisture     0.008 

0.008  X  100  ,  .  ^ 
=;  0.53  per  cent,  moisture. 

The  crucible  containing  the  dried  coal  is  now  heated  over 
a  Bunsen  burner  for  y/2  minutes,  then  over  the  blast-lamp 
for  3I/2  minutes  more,  taking  care  that  the  cover  of  the 
crucible  fits  closely.  Cool  in  the  desiccator.  Loss  in  weight 
equals  volatile  and  combustible  matter  plus  ^  of  the 
sulphur. 

Grams 
i     Crucible  -\-  cover  +  coal,  before  heating  7  minutes. . . .  26.109 

Crucible  +  cover  -j-  coal,  after  heating  7  minutes 25.569 

Volatile  and  combustible  matter  -f  ^  S 0.540 

0.540  X  100 


1-5 

-f-  V2  s. 


36  per     cent,    volatile    and     combustible    matter 


1  The  desiccator  should  contain  H2SO4  (C.  P.),  not  CaClg,  as  finely  pulverized  coal  is 
very  hydroscopic  even  in  pressure  of  CaClo. 


i:nginkering  chemistry 

The  crucible  and  contents  are  now  heated  over  a  Bunsen 
burner  (lid  of  crucible  removed)  until  all  carbonaceous 
matter  is  consumed.  Where  the  combustion  is  extremely- 
slow,  it  can  be  expedited  by  introducing  into  the  crucible  a 
slow  current  of  oxygen  gas  so  regulated  that  the  contents  of 
the  crucible  are  not  disturbed.  Replace  cover  of  crucible 
when  ignition  is  complete,  cool  in  desiccator  and  weigh. 

Grams. 
Crucible  +  cover  +  coal,  before  complete  combustion    25.569 
Crucible  +  cover  -j-  residue,  after  complete  combus- 
tion         24.669 


Fixed  carbon  +  ^  S 0.900 

o.Qoo  X  100       ^  ^      -,        , 

-^ 1=3  60  per  cent,  fixed  carbon  +  >^S. 

f   Crucible  +  cover  +  residue  of  coal,  after  complete 

combustion   (ash)    24.669 

Crucible  and  cover 24.61 7 


Ash    0.052 

O  OS2  X  100 

— ^ =,:  1.46  per  cent.  ash. 

1.5  o  -+    i- 

Resume. 

Per  cent. 

Moisture 0.53 

Volatile  and  combustible  matter  -f-  ^  S 36.00 

Fixed  carbon  +  ^  S 60.00 

Ash    3.46 


Total   ■. 99-99 

It  is  necessary,  now^,  to  determine  the  percentage  of  the  sul- 
phur present  in  the  coal  and  subtract  it  from  the  amounts  of 
volatile  and  combustible  matter  and  fixed  carbon. 

The  method  is  as  follows : 

Determination  of  Sulphur  in  Coal  by  the 
Eschka-Fresenius  Method. 

Preparation  of  Sample  and  Mixture.^ — Thoroughly  mix  on 
glazed  paper  i  gram  of  coal  and  3  grams  of  Eschka  mixture.  The 
mixture  is  prepared  by  thoroughly  incorporating  tv^o  parts  of 

1  Amer.  Soc.  Testing  Materials,  1914. 


ENGINEERING   CHEMISTRY  3 

magnesium  oxide  with  one  part  of  sodium  carbonate  by  passing 
through  a  40-mesh  screen.  By  this  method  of  preparation  the 
mixture  attains  a  uniformity  comparable  with  that  of  the  labo- 
ratory sample  of  coal  and  thorough  incorporation  is,  therefore, 
more  easily  effected. 

Transfer  to  a  No.  o  Royal  Berlin  crucible  or  platinum  cruci- 
ble of  similar  size  and  cover  with  about  i  gram  of  Eschka  mix- 
ture. 

Ignition. — On  account  of  the  amount  of  sulphur  contained  in 
artificial  gas,  it  is  preferable  to  heat  the  crucible  over  an  alcohol, 
gasoline  or  natural  gas  flame  or  in  an  electrically  heated  muffle 
(procedure  (a)  below).  The  use  of  artificial  gas  for  heating  the 
coal  and  Eschka  mixture  is  permissible,  provided  the  crucibles 
are  heated  in  a  muffle  (procedure  {h)  below). 

(a)  Heat  the  crucible,  placed  in  a  slanting  position  on  a 
triangle,  over  a  very  low  flame  to  avoid  rapid  expulsion  of  the 
volatile  matter,  which  tends  to  prevent  complete  absorption  of 
the  products  of  combustion  of  sulphur.  Heat  the  crucible 
slowly  for  30  minutes,  gradually  increasing  the  temperature  and 
occasionally  stirring  until  all  black  particles  disappear,  which 
is  an  indication  of  the  completeness  of  the  procedure. 

{h)  Place  the  crucible  in  a  cold  gas  muffle  and  gradually 
raise  the  temperature  to  870  to  925°  C.  (cherry-red  heat)  in 
about  I  hour.  Maintain  this  maximum  temperature  for  about 
i^  hours  and  then  allow  the  crucible  to  cool  in  the  muffle. 

Subsequent  Treatment. — Remove  and  empty  the  contents  into 
a  300  cc.  beaker  and  digest  with  100  cc.  of  hot  water  for  y^  to 
^  of  an  hour,  with  occasional  stirring.  Filter  and  wash  the  in- 
soluble matter  by  decantation.  After  several  washings  in  this 
manner,  transfer  the  insoluble  matter  to  the  filter  and  wash 
five  times,  keeping  the  mixture  well  agitated.  Treat  the  filtrate, 
amounting  to  about  250  cc,  with  10  to  20  cc.  of  saturated 
bromine  water,  make  slightly  acid  with  hydrochloric  acid  and 
boil  to  expel  the  liberated  bromine.  Make  just  neutral  to  methyl 
orange  with  sodium  hydroxide  or  sodium  carbonate  solution, 
then  add  i  cc.  of  normal  HCl.    Boil  again  and  add  slowly  from 


4  ENGINEERING   CHEMISTRY 

a  pipette  with  constant  stirring  lo  cc.  of  a  lo  per  cent,  solution 
of  barium  chloride  (BaClo.2H20).  Continue  boiling  for  15 
minutes  and  allow  to  stand  for  at  least  2  hours  at  a  temperature 
just  below  boiling.  Filter  through  an  ashless  filter  paper  and 
wash  with  hot  distilled  water  until  a  silver  nitrate  solution  show^s 
no  precipitate  with  a  drop  of  the  filtrate.  Place  the  wet  filter 
containing  the  precipitate  of  barium  sulphate  in  a  weighed  plat- 
inum or  alundum  crucible,  allowing  a  free  access  of  air  by  fold- 
ing the  paper  over  the  precipitate  loosely  to  prevent  spattering. 
Smoke  the  paper  off  gradually  and  at  no  time  allow  it  to  burn 
with  flame.  After  the  paper  is  practically  consumed  raise  the 
temperature  to  approximately  925°  C.  and  heat  to  constant 
weight. 

Thus : 

Grams. 

Amount  of  coal  taken 1.016 

Crucible  -f  BaS04  16.533 

Crucible    16.51 1 

BaSO^  0.042 

S  =  0.0057  gram. 

0.0057  X  100  ,  ^    ^ 

iiLJi:! —  0.56  per  cent.  S. 

1. 016  ^    ^ 

Taking  this  amount  and  subtraction  one-half  of  it  from  the 
volatile  and  combustible  matter  of  the  coal,  and  one-half  from  the 
fixed  carbon,  the  coal  analysis  will  be : 

Per  cent. 

Moisture 0.53 

Volatile  and  combustible  matter 35-72 

Fixed  carbon    59-72 

Sulphur     0.56 

Ash    3.46 

Total 99-99 

In  most  cases  the  sulphur  in  coal  exists  combined  with  iron  to 

form   ferrous   sulphide;   it  also   occurs   as   calcium   sulphate,   or 

both  forms  may  be  present  in  the  same  coal. 

To  determine  the   sulphur  trioxide   combined  with   the  lime, 

take  10  grams  of  the  finely  powdered  coal  and  digest  at  a  gentle 


ENGINEERING    CHEMISTRY  5 

heat,  2  hours,  in  a  solution  of  sodium  carbonate  (i.io).  It 
is  fihered,  washed  with  hot  water,  the  filtrate  made  acid  with 
hydrochloric  acid,  boiled  5  minutes  and  the  sulphur  trioxide  pre- 
cipitated with  barium  chloride  solution. 

Determination  of  Sulphur  by  the  Peroxide  Fusion  Method. 

This  method  is  most  conveniently  carried  out  in  the  bomb  which  is 
a  part  of  the  Parr  calorimeter/  the  fusion  resulting  from  a  heat  deter- 
mination being  especially  well  suited  to  this  purpose.  The  charge  con- 
sists of  0.5  gram  of  the  air-dry  laboratory  sample  of  coal,  i  gram  of 
potassium  chlorate  pulverized  to  about  20-mesh,  and  10  grams  by  measure 
of  sodium  peroxide  of  the  grade  regularly  prescribed  for  calorimetric 
purposes.  For  mixtures  intended  only  for  sulphur  determinations,  oven- 
drying  is  unnecessary.  The  coal  and  potassium  chlorate  are  first  added 
to  the  bomb  or  fusion  cup  and  thoroughly  mixed,  being  careful  to  break 
down  any  lumps  that  may  form.  The  sodium  peroxide  is  then  added, 
the  container  closed  and  ingredients  thoroughly  mixed  by  shaking. 

After  igniting  and  cooling  the  charge,  dissolve  the  fusion  in  a  covered 
beaker,  using  150  cc.  of  water.  Add  concentrated  hydrochloric  acid  just 
past  the  neutral  point.  This  will  require  from  25  to  30  ^c.  of  acid.  Add 
I  cc.  of  concentrated  HCl  (specific  gravity  1.19)  in  excess.  Filter  and 
wash  with  hot  water,  making  the  final  bulk  of  the  solution  approximately 
250  cc.  Heat  to  boiling  and  precipitate  the  sulphate  by  adding  10  cc. 
of  a  hot  10  per  cent,  solution  of  barium  chloride.  Continue  the  boiling 
for  15  minutes  and  allow  to  stand  for  at  least  2  hours  at  a  temperature 
just  below  boiling.  Filter,  wash  and  ignite  as  described  under  the 
Eschka-Fresenius  method.  Particular  care  should  be  taken  in  washing 
the  precipitate  obtained  by  this  method  in  order  to  remove  all  soluble 
salts  which  are  found  in  the  fusion  process. 

Determination  of  Sulphur  in  the  Washings  from  an 

Oxygen  Bomb  Calorimeter. 

After  the  combustion,  the  bomb  is  washed  out  thoroughly  with  dis- 
tilled water,  and  the  washings  collected  in  a  250  cc.  beaker.  Six  to  8  cc. 
of  dilute  (1:1)  hydrochloric  acid  containing  some  bromine  water  are 
then  added  and  the  solution  heated  to  boiling.  The  insoluble  matter  is 
filtered  off  and  washed  free  from  sulphates  with  hot  water.  The  filtrate 
and  washings,  which  should  have  a  total  volume  of  200  cc,  are  made 
just  neutral  to  methyl  orange  with  sodium-hydroxide  or  carbonate  solu- 

*  A  simpler,  inexpensive  bomb  is  described  in  Journal  Am.  Chem.  Soc,  Vol.  25, 
p.    184,   1903;   see  also  Noyes,   "Organic  Chemistry  for  the  Eaboratory,"  p.  21. 


6  Engine;b:ring  che^mistry 

tion,  I  cc.  of  normal  HCl,  is  added,  and  the  procedure  is  completed  as 
to  time  with  the  Eschka-Fresenius  method.) 

(If  an  odor  of  SO2  is  detected  in  the  escaping  gases  from  the  bomb, 
the  washings  cannot  be  used  for  the  sulphur  determination.  In  such  cases 
a  higher  oxygen  pressure  is  required.  Twenty  to  25  atmospheres  of 
oxygen  is  usuallj'^  sufficient  to  completely  oxidize  all  sulphur  to  SO3  in 
bombs  of  400  to  600  cc.  capacity.  Some  difficulty  may  be  experienced 
in  securing  complete  oxidation  of  all  sulphur  in  bombs  of  less  than  300  cc. 
capacity.  The  analyst  should  in  all  cases  check  his  results  from  time 
to  time  with  the  Eschka-Fresenius  method.) 

Determination  of  Phosphorus  in  Coal  and  Coke. 

To  the  ash  from  5  grams  of  coal  in  a  platinum  capsule  is  added  10  cc. 
of  nitric  acid  and  3  to  5  cc.  of  hydrofluoric  acid.  The  liquid  is  evaporated 
and  the  residue  fused  with  3  grams  of  sodium  carbonate.  If  unburned 
carbon  is  present  0.2  gram  of  sodium  nitrate  is  mixed  with  the  carbonate. 
The  melt  is  leached  with  water  and  the  solution  filtered.  The  residue  is 
ignited,  fused  with  sodium  carbonate  alone,  the  melt  leached  and  the 
solution  filtered.  The  combined  filtrates,  held  in  a  flask,  are  just  acidified 
with  nitric  acid  and  concentrated  to  a  volume  of  100  cc.  To  the  solution, 
brought  to  a  temperature  of  85°  C,  is  added  50  cc.  of  molybdate  solution 
and  the  flask  is  shaken  for  10  minutes.  The  precipitate  is  washed  sik  times, 
or  until  free  from  acid,  with  a  2  per  cent,  solution  of  potassium  nitrate, 
then  returned  to  the  flask  and  titrated  with  standard  sodium  hydroxide 
solution.  The  alkali  solution  may  well  be  made  equal  to  0.00025  gram 
phosphorus  per  cubic  centimeter,  or  0.005  per  cent,  for  a  5-gram  sample 
of  coal,  and  is  0.995  of  i/5  normal.  Or  the  phosphorus  in  the  precipitate 
is  determined  by  reduction  and  titration  of  the  molybdenum  with  per- 
manganate. 

Directions  for  Sampling  Coal,  or  Preparing  Samples 
for  Chemical  Analysis. 

Containers  for  Shipment  to  Laboratory. 

Samples  in  which  the  moisture  content  is  important  should  always  be 
shipped  in  moisture-tight  containers.  A  galvanized  iron  or  tin  can  with 
a  screw  top  which  is  sealed  with  a  rubber  gasket  and  adhesive  tape  is 
best  adapted  to  this  purpose.  Glass  fruit  jars  sealed  with  rubber  gaskets 
may  be  used,  but  require  careful  packing  to  avoid  breakage  in  transit. 

Samples  in  which  the  moisture  content  is  of  no  importance  need  no 
especial  protection  from  loss  of  moisture. 

Preparation  oe  Laboratory  Samples. 

The  method  of  preparing  a  suitable  sample  for  the  various  analytical 


Engine:e:ring  chemistry 


determinations    that    are    required    in    coal    analysis    should    conform    as 
nearly  as  practicable  to  the  following  requirements : 

1.  A  uniform  distribution  of  coal  and  impurities  must  be  maintained 
throughout  the  process  of  reducing  to  the  final  powdered  sample.  This 
should  be  insured  by  thorough  mixing  between  each  dividing  or  quarter- 
ing process,  and  by  having  due  regard  to  the  ratio  of  size  of  largest 
impurities  and  weight  of  sample. 

2.  Unrecorded  changes  in  moisture  during  the  procedure  of  sampling 
must  be  reduced  to  a  minimum. 

Coal,  especially  when  in  a  pulverized  condition,  is  exceedingly  sus- 
ceptible to  change  in  moisture  content.  The  general  tendency  is  loss  of 
moisture  on  dividing  to  finer  sizes.  This  may  amount  to  several  per  cent, 
in  coal  that  has  not  been  previously  air-dried. 

The  equilibrium  point  of  the  moisture  in  pulverized  coal  varies  with 
the  temperature  and  humidity  of  the  air.  Coal  that  has  reached  equili- 
brium with  respect  to  moisture  in  an  atmosphere  of  low  humidity  will 
reabsorb  moisture  if  placed  in  an  atmosphere  of  higher  humidity.^ 

3.  Due  regard  must  be  given  to  the  tendency  of  coal  to  absorb  oxygen 
and  deteriorate  in  heating  value.  The  time  of  air-drying  must,  therefore, 
be  as  short  as  possible  and  should  correspond  to  the  statements  given 
under  Method  No.  i,  below. 

Methods  of  Sampung, 

The  following  alternate  methods  of  preparing  laboratory  coal  samples 
are  recommended  as  conforming  to  the  theoretical  requirements  set  forth 
in  the  preceding  paragraphs,  and  as  being  commercially  practicable  for 
technical  coal  analysis : 

Method  No.  i. — Samples  of  coal  received  by  the  laboratory  which 
exceed  5  pounds  in  weight,  or  4-mesh  (length  of  openings  in  sieve  not  to 
exceed  0.20  inch)  in  size  should  be  rapidly  crushed  to  4-mesh,  mixed  and 
reduced  to  not  less  than  5  pounds.  This  portion  is  then  transferred  to  a 
weighed  sheet-metal  pan,  spread  out  to  a  depth  of  i  inch  and  at  once 
weighed.  The  pan  is  placed  in  a  special  drier"  and  the  coal  allowed  to 
air-dry  in  circulating  air  at  10°  to  15°  C.  above  the  sampling-room  tem- 
perature, until  the  rate  of  moisture  loss  is  less  than  o.i  per  cent,  per 
hour,  as  shown  by  2  weighings  made  at  intervals  of  2  to  4  hours.  In 
most  cases  Appalachian  bituminous   coal   and   anthracite  will  be   air-dry 

^  For  experimental  data  on  moisture  changes  in  coal  samples,  see  N.  W.  Lord, 
"Experimental  Work  of  the  Chemical  Eaboratory,"  Bulletin  No.  28,  Bureau  of  Mines, 
pp.    13-16,    1911. 

^  For  details  of  air-drying  oven  see  Bownocker,  lyord  and  Somermeier,  "Coal," 
Bulletin  No.  9,  4th  Series,  Ohio  Geological  Survey,  p.  312,  1908;  or  F.  M.  Stanton 
and  A.  C.  Fieldner,  "Methods  of  Analyzing  Coal  and  Coke,"  Technical  Paper  No.  8, 
Bureau  of  Mines,  p.  4,  19 12;  or  E.  E-  Somermeier,  "Coal,  Its  Composition,  Analysis, 
Utilization  and  Valuation,"  p.   71,   McGraw-Hill   Book   Co.,    1912. 


8  ENGINEERING   CHEMISTRY 

if  left  in  the  drier  over  night.     IlHnois  coals  may  require  48  hours  and 
lignites  "jz  hours  for  air- drying. 

Immediately  after  the  last  weighing  has  been  made,  the  entire  sample 
should  be  rapidly  pulverized  to  lo-mesh  size,  mixed  and  reduced  to  500 
grams  with  an  enclosed  riffle  sampler^  whose  sub-divisions  are  not  more 
than  ^  inch  apart.  This  500  gram  portion  is  at  once  transferred  to  the 
porcelain  jar  (8.95  inches  in  diameter  and  9.65  inches  high)  of  an  Abbe 
ball  mill,  sealed  air-tight  and  then  pulverized  to  60-mesh.  Bituminous 
coals  require  about  Yz  hour  and  anthracites  about  2  hours  to  pulverize  to 
60-mesh. 

The  jar  should  contain  about  one-third  of  its  volume  of  i  inch,  well- 
rounded  flint  pebbles,  and  should  be  rotated  at  about  60  revolutions  per 
minute.  The  coal  is  removed  from  the  porcelain  jar  by  emptying  the 
contents  on  a  }/^-inch  screen,  which  is  vigorously  shaken  a  moment  to 
detach  the  coal  from  the  pebbles.  The  sample  is  then  reduced  to  the 
final  laboratory  sample  of  approximately  60  grams  by  successively  halving 
it  with  a  small,  enclosed  riffle  sampler.  All  of  the  final  sample  should 
then  be  put  through  the  60-mesh  sieve,  and  at  once  transferred  to  a  4-ounce 
wide-mouthed  bottle  which  is  securely  ^zlosed  with  a  well-fitting  rubber 
stopper.  To  avoid  moisture  change,  the  sieve  should  be  covered  while 
sifting.  Usually  a  few  particles  of  coarse  material  remain  on  the  sieve. 
These  must  be  rubbed  down  on  a  bucking  board  or  mortar  to  60-mesh, 
and  thoroughly  mixed  with  the  sample.  (If  one  could  be  certain  that  all 
of  each  sample  would  pass  the  60-mesh  sieve  it  would  be  preferable  to 
omit  sieving,  since  it  has  a  tendency'  to  segregate  the  particles  of  slate 
and  pyrite  and  offers  an  opportunity  for  change  in  moisture  content. 
On  the  other  hand,  if  the  sieving  is  omitted  there  is  great  danger  of 
rather  coarse  particles  of  slate  and  pyrite  being  present  in  the  final 
sample.)  The  mixing  and  reducing  of  the  sample  after  removal  from 
the  ball  mill  should  be  done  rapidly  to  minimize  loss  or  absorption  of 
moisture.  The  total  time  elapsing  from  the  opening  of  the  ball  mill  jar 
to  the  stoppering  of  the  laboratory  sample  bottle  need  not  exceed  2  or 
3  minutes. 

The  total  loss  in  weight  of  samples  while  air-drying  is  reported  as 
air-drying  loss.     The  moisture  in  the  coal  "as  received"  =  moisture  in 

.     ,   .    ,         ,  ,  ^   100  —  air-drying  loss    ,      .     ,     . 
an  air-dned  coal  X — r  air-drying  loss. 

Method  No.  2. — Samples  of  coal  if  larger  than  4-mesh  (0.20  inch) 
should  be  rapidly  reduced  to  5  pounds  at  4-mesh  or  finer  as  in  Method 
No.  I. 

^  For  details  of  riffle  sampler  see  Bulletin  No.  9,  4th  Series,  Ohio  Geological 
Survey,  p.  313,  1908;  or  E.  E.  Somermeier,  "Coal,  Its  Composition,  Analysis,  Utili- 
zation and  Valuation,"  p.  73,  McGraw-Hill  Book  Co.,   19 12. 


KNGINEERING    CHEMISTRY 


This  5-poimd  portion  is  quickly  passed  through  a  suitable  crushing 
apparatus, — rolls  or  enclosed  coffee-mill  type  of  grinder, — adjusted  to 
crush  to  10  or  20-mesh  size.  A  60-grani  moisture  sample  should  be 
taken,  without  sieving,  immediately  after  the  material  has  passed  through 
the  crushing  apparatus.  This  sample  should  be  taken  with  a  spoon 
from  various  parts  of  the  10  or  20-mesh  product,  and  should  be  placed 
directly  in  a  rubber-stoppered  bottle. 

The  main  portion  of  the  sample  is  further  pulverized  until  all  passes 
through  a  20-mesh  sieve.  It  is  then  thoroughly  mixed  and  reduced  on 
the  riffle  to  about  120  grams,  which  is  pulverized  to  60-mesh  by  any 
suitable  apparatus  without  regard  to  loss  of  moisture.  After  this  sample 
has  been  passed  through  the  60-mesh  sieve  it  is  again  mixed  and  divided 
on  a  small  riffle  to  60  grams.  The  final  sample  should  be  transferred  to 
a  4-ounce  rubber-stoppered  bottle. 

Moisture  is  determined  at  105°  C.  on  i  gram  portions  of  the  60-mesh 
sample  and  on  5  gram  portions  of  the  20-mesh  sample  by  the  method 
described  in  this  report.  In  the  latter  case  the  drying  is  continued  1^/2 
hours.  The  analysis  of  the  60-mesh  coal,  which  has  become  partly  air- 
dried  during  sampling,  is  calculated  to  the  dry  basis  by  dividing  each 
result  by  i  minus  its  content  of  moisture.  The  analysis  of  the  coal  "as 
received"  is  computed  from  the  "dry-coal"  analysis  by  multiplying  by  i 
minus  the  total  moisture  found  in  the  20-mesh  sample. 

Coal  containing  visible  superficial  moisture  should  be  spread  out  in 
weighed  pans  and  allowed  to  air-dry  as  in  Method  No.  i,  or  at  room 
temperature ;  otherwise  considerable  loss  of  moisture  will  take  place 
while  crushing  to  lo-mesh  size.  The  percentage  of  loss  in  weight  is 
recorded  and  the  analysis  of  the  air-dried  sample  corrected  to  the  "as 
received"  basis,  as  described  in  Method  No.  i. 

Notes  on  the  Two  Methods  oe  Sampling. 

The  first  method  is  preferable  for  the  preparation  of  laboratory  samples 
that  are  intended  for  highly  accurate  analysis.  The  unavoidable  loss  of 
moisture  during  sampling  is  less  than  by  the  second  method,  especially  in 
the  case  of  samples  of  wet  or  freshly  mined  coal.  Such  samples  lose 
moisture  rapidly  on  exposure  to  air.  Air-drying  should  not  be  unneces- 
sarily prolonged,  as  otherwise  an  appreciable  loss  of  heating  value  from 
oxidation  takes  place. 

The  second  method  can  be  more  readily  adapted  to  the  apparatus  at 
hand  in  the  ordinary  laboratory,  as  it  does  not  require  the  special  air- 
drier  or  ball  mills  for  pulverizing  the  coal.  The  method  admits  hand- 
ling a  large  number  of  samples  in  a  short  time.  The  moisture  obtained 
by  this  method  is  usually  somewhat  less  than  that  obtained  by  the  first 
method.  In  the  case  of  coals  that  have  lost  part  of  their  moisture  con- 
tent through  being  exposed  to  the  atmosphere,  like  the  usual  commercial 


lo  engine:e:ring  che:mistry 

shipments,   this   difference  need   not   exceed  0.5   per   cent.     Wet   samples 
must  be  partly  air-dried. 

Coals  which  are  high  in  sulphur  and  slate  should  preferably  be  pul- 
verized to  80-mesh. 

The  disk  pulverizer  is  not  adapted  to  the  fine  grinding  of  coke  and 
anthracite ;  the  abrasive  action  of  the  coke  on  the  iron  surface  of  the 
disk  pulverizer  seriously  contaminates  the  sample ;  and  anthracite  is 
heated  by  the  rubbing  surfaces  to  a  degree  that  may  change  the  com- 
position of  the  sample. 

A  chipmunk  jaw  crusher  is  well  adapted  to  crushing  the  sample  re- 
ceived at  the  laboratory  to  4-mesh  size,  and  a  roll  crusher  for  reducing 
the  4-mesh  material  to  10  to  20-mesh  size.  The  rolls  have  one  disad- 
vantage, in  that  with  some  coals,  flakes  are  formed  which  must  be  broken 
up  by  rubbing  through  a  sieve  before  the  sample  can  be  reduced  on  the 
riffle  to  quantities  less  than  500  grams.  On  the  other  hand,  the  rolls  have 
a  large  capacity  and  are  easily  cleaned. 

Coffee  or  bone  mill  types  of  grinders  may  be  used  for  grinding  to  10  or 
20-mesh  size.  They  should  be  entirely  enclosed  and  provided  with  a 
covered  hopper  and  receptacle  of  sufficient  capacity  to  hold  the  entire 
5-pound  sample. 

A  new  porcelain  jar  ball  mill  and  pebbles  should  always  be  tested  for 
abrasion  before  use.  This  may  be  done  by  grinding  500  grams  of  sugar 
for  a  period  of  2  hours,  and  then  determining  the  ash  in  the  sugar;  or 
by  keeping  a  record  of  the  loss  in  weight  of  jar  and  pebbles  and  the 
weight  of  coal  ground. 

Determination  of  Moisture. 

The  report  of  the  sub-committee  II  on  moisture  in  coal  states :  In 
view  of  our  own  experience  and  that  of  the  chemists  who  co-operated 
with  a  sub-committee  of  the  International  Committee  on  Analyses^  it 
seems  needless  to  strive  at  present  in  ordinary  work  for  a  very  high 
degree  of  refinement  in  the  determination  of  moisture.  So  sensitive  are 
coals  to  humidity  changes  of  the  air  that  it  is  evidently  only  by  chance 
that  2  or  more  analysts  will  reach  the  same  results  for  moisture  in  a 
given  coal,  especially  if  they  live  in  different  cities  or  make  the  tests  on 
different  days  in  the  same  place.  To  the  truth  of  this  the  report  of  the 
above-mentioned  International  Committee  bears  abundant  testimony.  The 
variations  therein  shown  are  probably  due,  in  part,  to  lack  of  realization 
on  the  part  of  many  of  the  analysts  of  the  magnitude  of  the  changes  in 
moisture  content  that  may  arise  during  the  transfer  of  the  coal  from 
the  containing  vessel  to  the  drying  receptacle  and  during  the  weighing 

^  Proceedings,  Eighth  International  Congress  of  Applied  Chemistry,  Vol.  25,  p. 
4,    1912. 


i:ngine;e:ring  chemistry  ii 

operation.      Nevertheless    the    chances    of    variation    are    so    serious    that 
the  opening  statement  above  is  fully  justified. 

I.  Approximate  Method. 

Use  a  pair  of  shallow  weighing  capsules  with  ground  caps  or  other 
well-fitting  covers.  Suitable  forms  are  indicated  below.  Heat  these  under 
the  conditions  at  which  the  coal  is  to  be  dried,  stopper  or  cover,  cool 
over  concentrated  sulphuric  acid  for  30  minutes  and  weigh. 

Dip  out  with  a  spoon  or  spatula  from  the  container  two  portions  of 
coal  of  about  i  gram  weight  each,  put  these  quickly  into  the  drying 
vessels,  close,  and  weigh  at  once. 

An  alternative  procedure  (more  open  to  error),  after  transferring  an 
amount  sli"-htly  in  excess  of  I  gram,  is  to  bring  to  exactly  i-gram  weight 
(±0.5  milligram)  by  quickly  removing  the  excess  weight  of  coal  with 
a  spatula.  The  utmost  dispatch  must  be  used  in  order  to  minimize  the 
exposure  of  the  coal  until  the  weight  is  found. 

When  the  20-mesh,  5-gram  sampling  is  used,  it  is  to  be  weighed  in  a 
similar  measure  with  an  accuracy  of  2  milligrams. 

Further  procedure:  Quickly  place  the  vessels  open  in  a  preheated 
oven  (at  104  to  110°  C.)  through  which  passes  a  current  of  air  dried  by 
concentrated  sulphuric  acid.  Close  the  oven  at  once  and  heat  for  i  hour, 
or  in  the  case  of  the  20-mesh,  5-gram  sampHng,  for  i>^  hours.  Then 
open  the  oven,  cover  the  capsules  quickly  and  place  in  a  desiccator  over 
concentrated  sulphuric  acid.     When  cool,  weigh. 

Notes. 

I.  Although  watch  glasses  ground  to  fit  and  with  clamp  are  most  effec- 
tive drying  vessels  on  account  of  their  shallowness,  other  vessels  will  be 
found  more  convenient.  The  form  that  commends  itself  most,  because 
the  ash  determination  can  be  made  on  the  moisture  sample  without 
transfer,  is  a  porcelain  cup  of  the  size  and  shape  represented  by  No.  1716 
in  the  1913  catalog  of  Eimer  &  Amend  and  by  No.  1338  (No.  2  Royal 
Meissen  porcelain  capsule,  %  inch  deep  and  i^  inches  in  diameter)  in 
the  catalog  of  the  Scientific  Materials  Co.  of  Pittsburgh.  At  the  Bureau 
of  Mines  this  cup  is  used  with  a  well-fitting  aluminum  cover.  The  cup 
is  20  to  22  millimeters  deep  and  38  to  40  millimeters  wide.  Glass  capsules, 
as  used  by  S.  W.  Parr  and  recommended  by  the  International  Committee, 
are  likewise  suitable.  Those  tried  at  the  Bureau  of  Standards  are  15 
millimeters  deep  and  25  millimeters  wide,  somewhat  shallower  than  those 
of  Parr.  The  shallower  the  drying  vessels  are,  consistent  with  convenient 
handling,  the  quicker  and  more  perfect  is  the  drying.  The  Parr  capsules 
have  the  upper  part  of  the  wall  ground  on  the. outside  and  the  cap  is 
ground  on  the  inside,  leaving  a  smooth  edge,  a  feature  which  facilitates 


12  ENGINEERING    CHEMISTRY 

transfer  of  the  coal  to  the  ashing  vessel  if  the  same  sample  is  to  be  used 
for  determination  of  the  ash. 

2.  The  oven  must  be  so  constructed  as  to  have  a  uniform  temperature 
in  all  parts  and  a  minimum  of  air  space.  The  air  current  must  be  rapid 
enough  to  renew  the  gas  in  the  oven  frequently  when  the  oven  holds  from 
6  to  12  vessels  of  coal. 

The  cylindrical  form  of  oven  shown  in  the  Technologic  Paper  No.  8,  of 
the  Bureau  of  Mines,  page  5,  and  holding  6  crucibles,  is  well  adapted 
for  the  purpose ;  also  a  new  rectangular  oven  of  the  same  Bureau,  holding 
12  crucibles  and  measuring  inside  12J/2  inches  high  by  4  inches  wide 
and  141^  inches  long.  The  approximate  air  space  in  each  of  these  ovens  is 
0.05  cubic  foot.  With  this  type  of  oven,  of  small  air  space,  it  has  been 
found  at  the  Bureau  of  Mines  that  the  air  must  be  renewed  from  two  to 
four  times  a  minute  to  obtain  the  maximum  loss  in  weight  from  the  coal 
in  I  hour. 

The  International  Committee  in  its  report  recommends,  when  using 
air,  to  remove  one  of  the  capsules  from  the  oven  at  the  expiration  of  30 
minutes,  to  continue  heating  the  other  for  30  minutes  longer,  and  to  accept 
the  higher  loss  in  weight,  if  a  difference  is  shown,  as  may  happen  with 
certain  coals.  Our  committee  has  not  deemed  it  advisable  to  prescribe 
this  precaution,  both  on  account  of  the  added  labor  involved  in  testing 
four  portions  of  a  sample  instead  of  two  and  because  of  the  probable  error 
in  the  determination  of  the  true  moisture  content  is  so  large  as  to  render 
the  precaution  of  doubtful  value.  It  may,  however,  serve  a  useful  purpose 
at  times  and  is  a  permissable  modification  of  the  procedure  given  in  the 
approximate  method.  If  used,  however,  a  statement  to  that  effect  should 
accompany  the  report  of  analysis. 

II.  Methods  of  Greater  Accuracy. 

Method  No.  i. — This  method  is  like  the  approximate  method,  but  in- 
stead of  air  use  a  current  of  dry  carbon  dioxide  gas.  After  the  hour's 
heating,  open  the  oven,  cover  the  capsules,  place  them  in  a  vacuum  desic- 
cator over  concentrated  sulphuric  acid  and  exhaust  the  desiccator.  When 
cool,  slowly  admit  dry  air  and  weigh  at  once. 

Note. — Exhaustion  of  the  desiccator  is  necessary  in  order  to  avoid 
serious  error  in  weight  from  the  presence  of  carbon  dioxide  in  the  capsules 
when  these  are  weighed.  Although  carbon  dioxide  is  absorbed  by  coal 
at  room  temperature  there  is  no  absorption  above  100°  C.  Nitrogen  gas 
is  to  be  preferred  to  carbon  dioxide  because  its  density  is  so  near  that 
of  air  that  it  will  be  unnecessary  to  displace  it  from  the  capsules  before 
final  weighing.     If  this  gas  is  used,  a  vacuum  is  unnecessary. 

Method  N^o.  2. — This  method  is  applicable  to  the  test  of  only  i 
sample  at  a  time.     It  is  like  Method   No.   i,  but  uses  a  current  of  dry 


ENGINKERING    CHEMISTRY  I3 

nitrogen  gas  and  instead  of  a  shallow  capsule,  a  U-tube  with  well-ground 
stoppers,  and  any  special  form  of  oven  in  which  the  tube  can  be  hung  at  a 
temperature  of  104  to  110°  C.  Fill  the  tube  with  dry  nitrogen  before 
taking  its  weight  empty,  and  weigh  always  with  a  counterpoise  tube  of 
about  the  same  displacement  and  weight.  Introduce  about  a  gram  of 
the  coal  quickly  through  a  short  and  wide-stem  funnel  without  attempt 
to  secure  a  weight  of  exactly  i  gram.  Before  hanging  the  tube  in  the 
preheated  oven  pass  nitrogen  to  displace  all  air,  and  continuously  while 
heating.  When  the  last  trace  of  moisture  has  disappeared  from  the  outlet 
of  the  tube,  remove  from  the  oven  and  let  cool  with  the  gas  still  passing. 
When  cool  close  the  cocks,  hang  in  the  balance  case  for  15  minutes  and 
after  opening  one  cock  weigh  with  counterpoise.  The  counterpoise  need 
not  be  filled  with  nitrogen. 

As  a  check  the  water  given  off  may  be  collected  in  sulphuric  acid  and 
weighed,  care  being  taken  to  keep  the  absorption  vessel  full  of  nitrogen. 
The  weight  of  water  thus  obtained  is  a  little  higher  than  that  found 
indirectly. 

Method  No.  3. — This  method  is  for  use  when  time  does  not  press. 
Dry  in  a  vacuum  desiccator  over  sulphuric  acid  of  maximum  concentra- 
tion for  3  and  7  days,  longer  if  necessary. 

The  vacuum  should  be  high — not  over  3  millimeters  of  mercury  press- 
ure— and  should  be  checked  by  a  manometer.  The  capsules  mentioned 
above  may  be  used.  Before  evacuating,  fill  the  desiccator  with  an  inert 
gas,  and  before  opening  the  desiccator  carefully  let  in  air  dried  by  sul- 
phuric acid.     Weigh  immediately. 

This  method  is  easy  of  execution  and  is  sound  of  principle,  since  a 
possible  error  due  to  loss  of  gaseous  constituents  is  negligible.  It  is 
important,  however,  when  using  a  high  vacuum,  to  produce  this  gradually 
since,  if  suddenly  produced  before  most  of  the  moisture  and  air  have 
escaped  there  may  be  projection  of  the  coal  from  the  capsule. 

It  has  not  been  deemed  advisable  to  recommend  the  xylene  method 
of  Constam  (boiling  a  large  weight  of  coal  with  xylene  and  collecting 
and  measuring  the  water  that  distils  over)  since,  though  promising,  the 
method  has  not  been  subjected  to  exhaustive  test.  The  same  statement 
applies  to  a  method  said  to  be  in  use  in  Germany,  which  consists  in  heating 
the  coal  in  a  vacuum  at  the  temperature  of  boiling  alcohol  for  an  hour. 
So  far  as  tests  made  at  the  Bureau  of  Standards  allow  of  judging,  the 
method  justifies  the  claims  that  have  been  made  for  it,  and  it  will  be 
tested  further.  An  article  on  the  subject  by  P.  Schlaflfer  has  been  recently 
published.^ 

^  Z.  angew.  Chem.,  Vol.  27,  p.   52   (1914). 


14  EnginE£:ring  chemistry 

Determination  of  Volatile  Matter. 
I.  MuFFi,E  Method. 

It  is  recommended  that  for  volatile  matter  determinations  a  lo  gram 
platinum  crucible  be  used  having  a  capsule  cover,  or  one  fitting  closely 
enough  so  that  the  carbon  from  bituminous  or  lignite  coals  does  not 
burn  awa}'  from  the  under  side.  The  capsule  cover  fits  inside  of  the 
crucible  and  not  on  top.  The  crucible  with  i  gram  of  coal  is  placed  in 
a  muffle  maintained  at  approximately  950°  C.  for  7  minutes.  With  a 
muffle  of  the  horizontal  type,  the  crucible  should  not  rest  on  the  floor 
of  the  muffle  but  should  be  supported  on  a  platinum  or  nichrome  triangle 
bent  into  a  tripod  form.  After  the  more  rapid  discharge  of  the  volatile 
matter,  well  shown  by  the  disappearance  of  the  luminous  flame,  the  cover 
should  be  tapped  lightly  to  more  perfectly  seal  the  crucible  and  thus 
guard  against  the  admission  of  air. 

II.  ALTERNATE  Method. 

One  gram  of  coal  is  placed  in  a  platinum  crucible  of  approximately 
20  cc.  capacity  (35  millimeters  in  diameter  at  the  top  and  35  millimeters 
high).  The  crucible  should  have  a  tightly  fitting  cover,  as  above.  The 
crucible  is  placed  in  the  flame  of  a  Meker  burner,  size  No.  4,  having 
approximately  an  outside  diameter  at  the  top  of  25  millimeters  and  giving 
a  flame  not  less  than  15  centimeters  high.  The  temperature  should  be  from 
900  to  950°  C.  determined  by"  placing  a  thermo  couple  through  the  perfo- 
rated cover,  which  for  this  purpose  may  be  of  nickel.  The  junction  of  the 
couple  should  be  placed  in  contact  with  the  center  of  the  bottom  of  the 
crucible.  Or  the  temperature  may  be  indicated  by  the  fusion  of  pure 
potassium  chromate  in  the  covered  crucible  (fusion  of  KsCrOs,  940°  C). 
The  crucible  is  placed  in  the  flame  about  i  centimeter  above  the  top  of  the 
burner  and  the  heating  is  continued  for  7  minutes.  After  the  main  part 
of  the  gases  have  been  discharged  the  cover  should  be  tapped  into  place 
as  above  described. 

When  the  gas  pressure  is  variable  it  is  well  to  use  a  U-tube  attachment 
to  the  burner  to  show  the  pressure. 

For  lignites  a  preliminary  heating  of  5  minutes  is  carried  out,  during 
which  time  the  flame  of  the  burner  is  played  upon  the  bottom  of  the 
crucible  in  such  a  manner  as  to  bring  about  the  discharge  of  volatile 
matter  at  a  rate  not  sufficient  to  cause  sparking.  After  the  preliminary 
heating  the  crucible  is  placed  in  the  full  burner  flame  for  7  minutes  as 
above  described. 

For  coke  or  anthracite  a  capsule  cover  or  nested  crucible  should  always 
be  used. 


ENGINKERING    CHEMISTRY 


15 


Determination  of  Ash. 

One  gram  of  coal,  either  freshly  weighed  or  that  which  has  been  used 
for  the  moisture  determination,  is  ignited  in  a  shallow  porcelain  capsule.^ 
A  low  temperature  should  at  first  be  used,  obtained  by  placing  the  capsule 
just  above  the  tip  of  a  Bunsen  flame  turned  down  to  2  or  3  inches  in 
height.  Frequent  stirring  with  a  platinum  or  nichrome  wire  is  necessary. 
After  a  considerable  part  of  the  carbon  is  burned  off  the  flame  should 
be  turned  up  and  the  heat  increased  to  low  redness.  The  capsule  should 
finally  be  transferred  to  a  muffle  maintained  at  dull  or  cherry-red  tem- 
perature between  700°  and  750°  C.  From  20  to  30  minutes  will  ordinarily 
be  required  for  the  first  part  of  the  process,  while  10  minutes  should  be 
ample  for  the  heating  in  the  muffle. 

If  a  muffle  is  used  for  the  whole  process,  the  heating  should  be  started 
with  the  muffle  cold  or  on  the  hearth  at  a  low  temperature. 

Corrected  Ash. 

The  application  of  a  correction  for  sulphur  present  in  the  iron  pyrites 
depends  largely  upon  the  use  to  be  made  of  the  results.  For  technical 
purposes  it  may  well  be  omitted.  For  comparative  purposes,  especially 
where  use  is  to  be  made  of  the  pure  coal  or  unit  values,  it  should  be 
applied.  Five-eighths  of  the  sulphur  present  in  the  pyritic  form,  if  added 
to  the  ash,  would  restore  the  iron  sulphide  to  the  original  form  as 
weighed. 

While  with  certain  types  of  coal,  especially  those  extensively  used  for 
steaming  purposes,  averaging  15  to  20  per  cent,  ash,  it  is  evident  that 
there  is  a  volatile  ash  constituent  of  considerable  importance  due  to 
hydration  of  clayey  material,  in  our  present  state  of  information  as  to 
the  uniform  distribution  of  this  constituent  it  does  not  seem  advisable  to 
incorporate  it  in  technical  analyses.  For  a  comparative  study,  however, 
a  correction  for  this  type  of  ingredient  cannot  be  avoided.  The  factor 
which  has  received  extended  application  is  an  increase  of  8  per  cent,  of 
the  ash  as  weighed  to  represent  this  volatile  constituent. 

AllowabIvR  Variations. 


No  carbonates  present 

Carbonates  present 

Coals  with  more  than  12  per  cent,  ash 


vSame 
analyst, 
per  cent. 


0.2 
05 


Different 

analyst, 

per  cent. 


0-3 

o.i 


The  analyses  of  a  few  representative  coals  are  here  given  : 

^  Such   dishes    as    are    listed   under   the    name    of    "Gluh-Schalchen,"    No.    5837    in 
Greiner  and  Friedrichs,  catalog,    19 12. 


i6 


ENGINEERING    CHEMISTRY 


"Bog  Head  Cannel''  Coae. 

Per  cent. 

Moisture     0.60 

Volatile  and  combustible  matter 71.30 

Fixed  carbon    21.20 

Sulphur    0.30 

Ash    6.60 


Total    100.00 

"Pittsburgh  Bitetminous"  Coae. 

Per  cent. 

Moisture     1.28 

Volatile  and  combustible  matter 37-36 

Fixed  carbon    57-33 

Sulphur    0.72 

Ash    3.31 


Total   100.00 

"Penn  Anthracite,"  Wiekes-Barre,  Dee.  &  Hudson 
Canae  Co.'s  "Vein  No.  5." 

Per  cent. 

Moisture     4.182 

Volatile  and  combustible  matter 4-283 

Fixed  carbon    85.320 

Sulphur 0.794 

Ash    5.421 


Total    100.00 

It  is  found  in  practice  that  coal  from  the  same  vein  or  seam 
varies  in  composition  with  the  size  of  the  coal,  the  percentage  of 
ash  increasing  as  the  size  of  the  coal  diminishes.  Thus,  samples 
collected  from  the  Hauto  Screen  Building  of  Lehigh  Coal  and 
Navigation  Co.,  Pa.,  gave  the  following: 


size  of  coal 


Moisture 


Volatile 
matter 


Fixed 
carbon 


Sulphur 


Ash 


Total 


Egg 

Stove  

Chestnut. . . 
Pea 

Buckwheat. 


1.722 
1.426 
1.732 
1.760 
1.690 


3-518 
4.156 
4.046 

3.894 
4.058 


88.489 
83.672 
80.715 

79045 
76.918 


0.609 
0.572 
0.841 
0.637 

0.714 


5.662 
10.174 
12.666 
14.664 
16.620 


100 
100 
100 
100 
100 


These  coals  are  separated  into  different  sizes  according  to  th( 


ENGINKERING    CHE:mISTRY 


17 


mesh  of  the  screen  over  which  they  pass.  The  sizes  noted  in  the 
above  table  passed  over  and  through  sieve  meshes  of  the  follow- 
ing dimensions : 


Broken  or  grate  size 

Egg 

Stove  "   

Chestnut  "   

Pea  '  •   

Buckwheat  No.  i.       

Buckwheat  No.  2.  (Rice) 
Buckwheat  No.  3.  (Barle} 


through 


4.00  in. 

over 

2.50  m 

2.50 

1.75 

'•75 

T.25 

1-25 

0.75 

0.75 

050 

0  50 

0.25 

Analysis  of  a  sample  of  ash  of  a  Welsh  coal,  by  J.  A.  Phillips, 
gave: 

Per  cent. 

Silica 26.87 

Akimina  and  iron  oxide  56.95 

Lime    5.30 

Magnesia    1.19 

Sulphuric  acid    7.23 

Phosphoric    acid    0.74 

Undetermined  1.72 

Total    100.00 

An  analysis,  by  Gautier,  of  the  ash  of  a  sample  of  English 
coke,  gave  the  following: 

Per  cent. 

Silica   42.10 

Alumina    3440 

Calcium  Carbonate   4.80 

Magnesium  carbonate    0.40 

Calcium    sulphate    12.55 

Ferric  oxide   5.28 

Total   99-53 


Method  of  Testing  Coal,  for  Amount  of  Slate. 

A   quick  and   useful   method   of   determining  the   amount   of 
slate  in  the  small  sizes  of  prepared  coal  is  employed  by  the  Dela- 


l8  ENGINEERING   CHEMISTRY 

ware,  I^ackawanna  &  Western  Coal  Department  at  its  mines  in 
Pennsylvania.  When  the  railroad  car  is  being  loaded,  samples 
of  coal  are  collected  which  aggregate  lo  pounds.  About  one- 
fourth  of  this  lo-pound  sample  is  set  apart  at  the  testing  house 
for  the  slate  determination.     The  method  is  as  follows : 

A  solution  is  prepared  by  mixing  sulphuric  acid  with  water 
until  the  mixture  shows  specific  gravity  of  1.7  by  hydrometer 
test.  This  solution  is  placed  in  an  earthenware  jar.  A  perfo- 
rated copper  vessel,  of  several  times  the  capacity  of  the  coal 
sample,  is  suspended  in  the  solution.  On  the  sample  being  poured 
into  the  copper  receptacle  and  agitated,  the  slate  sinks,  while  the 
coal  floats  on  the  solution.  The  coal  is  skimmed  off,  washed, 
weighed  and  compared  with  the  total  weight  of  the  coal  and 
slate.  This  leaves  nothing  to  the  discrimination  of  an  inspector 
as  to  what  should  be  classed  as  slate.^ 

Resume. 

In  selecting  a  sample  of  coal  for  analysis,  it  is  absolutely 
essential  that  it  be  a  representative  one  and  quickly  taken,  during 
delivery  of  the  coal,  to  prevent  loss  of  surface  moisture  by 
evaporation.  The  sample  should  be  collected  in  an  air-tight 
vessel.  The  coal  and  vessel  are  weighed,  the  coal  spread  upon 
a  non-absorbent  surface  and  dried  at  70°  F.  for  24  hours. 

It  is  then  weighed  with  the  receptacle — :  the  difference  in 
weight  represents  surface  moisture. 

The  coal  is  passed  through  a  crusher  rapidly  and  then  trans- 
ferred to  an  Abbe  pebble  pulverizer.^  This  machine  is  air-tight 
and  reduces  all  the  coal  so  that  it  passes  through  a  200-mesh 
sieve.  This  pulverizer  has  the  advantage  that  during  the  grind- 
ing of  the  coal  no  moisture  is  lost  or  absorbed.  After  pulveriz- 
ation the  coal  is  immediately  transferred  to  a  bottle,  tightly  stop- 
pered— ready  for  the  analysis. 

An  example  of  the  above  operation  can  be  stated  as  follows : 

1  Consult:    "Coal  Ash,"  by  John  W.  Cobb,  B.  Sc.   (London),  7.  Soc.  Chem.  Ind., 
Jan.  12,  1904,  pp.  11-15. 
''Fig.   1. 


KNGINKKRING    CHEMISTRY 


19 


Grams. 

Weight  of  coal  and  can  before  air-drying  at  70°  F 4327. 

Weight  of  coal  and  can  after  air-drying  at  70°  F 4206. 

Weight  of  can  225. 

:.  Weight  of  coal  wet  less  can 4102. 

:.  Weight  of  coal  dry  less  can 3981. 

Moisture  in  coal  after  air-drying  24  hours  at  70°  F 121. 

Percentage  of  moisture  after  air-drying 2.9 

Percentage   of  moisture  in  the   air-dried  coal,   as   per 

direction,  page  18  2.1 

Total  moisture 5.0 

It  will  be  seen  from  this  example  that  2.9  per  cent,  of  moisture 
with  the  coal  is  surface  moisture  and  of  no  value  to  the  pur- 
chaser.   It  is  of  value,  however,  to  the  contractor,  for  unless  this 


Fig.   I. 


surface  moisture  is  determined  and  deducted,  he  is  paid  for 
water. 

Suppose  the  consignment  of  coal  is  1,000  tons;  2.9  per  cent,  of 
this  is  29  tons,  in  other  words  58,000  pounds  of  surface  water  are 
present,  costing  the  purchaser,  with  coal  selling  at  $4  per  ton. 
$116. 

Referring  now  to  specification  page  22,  it  will  be  noticed  that 
moisture  is  allowed  jn  coal  up  to  1.5  per  cent.,  all  amounts  over 
this  the  contractor  pays  a  rebate  or  penalty  for  each  ^  per  cent. 


20  ENGINEERING    CHEMISTRY 

of  moisture.  This  rebate  is  generally  arranged  (when  large 
quantities  of  coal  are  sold)  between  the  contractor  and  pur- 
chaser, and  varies  greatly.  Taking  the  determination  of  moisture 
in  the  analysis  given  on  page  i8,  amounting  to  5.0  per  cent,  total, 
the  rebate  would  be  upon  3.5  per  cent,  moisture. 


SPECIFICATIONS  FOR  ANTHRACITE  COAL. 

Department  of  Docks  and  Ferries,  New  York  City,  N.  Y. 
Quality  ArticeE  I.     All  the  coal  to  be  furnished  under  this 

of  Coal.  Contract  shall  be  free  burning  white  ash  and  of  some 
of  the  following  grades : 

Susquehanna  Coal  Company,  "Susquehanna"; 
Lehigh  Valley  Coal  Company,  "Wyoming" ; 
Delaware,  Lackawanna  &  Western,  "Scranton" ; 
Delaware  &  Hudson,  "Lackawanna" ; 
Pennsylvania  Coal  Company,  "Pittston" ; 
Lehigh  &  Wilkes-Barre,  "Wilkes-Barre" ; 

or  some  other  grade  equal  thereto  and  satisfactory  to 
and  approved  by  the  Engineer.  When  demanded  by 
the  Engineer,  satisfactory  evidence  shall  be  furnished 
of  the  name  of  the  mine  from  w^hich  the  coal  fur- 
nished is  mined. 

All  the  coal  required,  except  in  cases  of  emergency, 
must  be  delivered  direct  from  boats,  and  must  be  of 
the  best  quality  of  white  ash  anthracite  coal.  It  shall 
be  of  the  size  hereafter  mentioned,  well  screened,  dry, 
clean,  fresh  mined  and  in  good  merchantable  condi- 
tion. When  it  becomes  necessary  to  deliver  coal  from 
yard  or  pocket,  permission  of  the  Engineer  must  be 
obtained. 
Bills  of  Article  2.     An  original  Bill  of  Lading  for  every 

Lading.  cargo  of  coal  supplied  must  be  furnished  the  Engineer 
by  the  Contractor,  also  an  original  Bill  of  Lading  must 
be  furnished  the  Engineer  by  the  shipper  from  the 
shipping  port. 


KNGINKERING    CHEMISTRY  21 

Unit  ot  AritclE  3-     A  ton  in  this  contract  shall  be  taken 

Weight.        to  mean  a  ton  of  2,240  pounds. 

Size  of  Article  4.     Unless  otherwise  directed  or  allowed 

Coal.  all  coal  furnished  shall  be  known  as  "pea"  coal  and 

conform  to  the  following  standard :     That  will  pass 

through  a  screen  having  3/J-inch  square  meshes  and 

will  pass  over  a  screen  having  5^ -inch  square  meshes. 

Analysis.  ArticeE  5.     All  coal  shall  be  subject  to  chemical 

analysis  at  any  time  the  Engineer  shall  require  11. 
When  analyzed  it  must  contain  not  more  than  the  fol- 
lowing per  cents,  of  impurities : 

Per  cent. 

Ash   12.00 

Sulphur    1. 00 

Moisture    1.50 

In  case  the  ash  exceeds  12  per  cent.,  but  is  less  than  16  per 
cent.,  or  the  moisture  exceeds  1.5  per  cent.,  but  is  less  than  3 
per  cent.,  the  Engineer  may,  at  his  discretion,  accept  the  deliv- 
ery for  an  amount  as  many  per  cent,  less  than  the  actual  delivery 
as  the  per  cent,  of  ash  exceeds  12  per  cent,  or  the  per  cent,  of 
moisture  exceeds  1.5  per  cent.;  or  in  case  both  ash  and  moisture 
arc  excessive,  for  as  many  per  cent,  less  than  the  actual  delivery 
as  the  sum  of  the  excess  in  per  cent,  of  ash  and  moisture  above 
12  per  cent,  and  1.5  per  cent.,  respectively,  is  of  the  total  delivery, 
but  no  coal  which  contains  more  than  16  per  cent,  of  ash,  or  3 
per  cent,  of  moisture  will  be  accepted,  except  at  the  discretion 
of  the  Engineer. 

Coal  to  be  analyzed  shall  be  taken  by  judicious  sampling,  and 
if  such  coal  analyzed  be  not  accepted  by  the  department,  the  Con- 
tractor shall  pay  the  cost  of  such  analyses,  and  all  other  expense 
and  damage  to  which  the  party  of  the  first  part  is  put  by  reason 
thereof :  otherwise  said  expense  shall  be  borne  by  the  said  party 
of  the  first  part. 


22 


Engine:e:ring  chemistry 
SPECIFICATIONS  FOR  BITUMINOUS  COAL. 


Interborough  Rapid  Transit  Co.,  N.  Y. 

PrEuminary  Specifications  for  Bituminous  Coal. 

Kind  of  Coal  must  be  a  good  steam,  coking,  run  of  mine, 

Coal.  bituminous  coal,  free  from  all  dirt  or  excessive  dust, 

a  dry  sample  of  which  will  approximate  the  Transit 

Company's  standard  in  heat  value  and  analysis. 


Carbon 

Volatile  matter 

Ash 

B.  t.  u.    per  lb. 

Sulphur 

l^fo 

20% 

9% 

14100.O 

1.5% 

The  table  of  heat  or  B.  t.  u.  values^  upon  which  the  bonuses  or 
deductions  will  be  made  is  as  follows : 

B.  t.  u.  Tables  of  Values. 

For  coal  which  is  found  by  test  to  contain  per  pound  of  dry  coal,  from 

15501  and  above 28c.  per  ton  above  standard 

15541  to  15500,  both  inclusive 27c. 


15401  to  15450  

15351  to  15400  "      

15301  to  15350  "      

15251  to  15300  "      

15201  to  15250  "      

15151  to  15200  "      

15101  to  15150  "      

15051  to  15100  "      

15001  to  15050  "      

14951  to  15000  "      

14901  to  14950  "      

14851  to  14900  "      

14801  to  14850  "       

14751  to  14800  "       

14701  to  14750  "       

14651  to  14700  "       

14601  to  14650  "       

14551  to  14600  "       

14501  to  14550  "       

14451  to  14500  "       

14401  to  14450  "       

14351  to  14440  "       

14301  to  14350  "       

14251  to  14300  "       

14201  to  14250  "       

14151  to  14200  "       

14101  to  14150  "       

^  For  methods  of  determination  of  the  B.  t. 


.26c. 
•25c. 

.24c.  " 

.23c. 

.22c.  " 

.2IC. 
.20c. 
.19c. 

.i8c. 
.17c. 
.  i6c. 
.15c. 
.  14c. 
.13c. 

.  I2C.  " 

.IXC.  " 

.IOC. 

.  9c. 

.  8c. 

.  7c. 

.  6c. 

.  5c. 

.  4c. 

.  3c. 

.    2C.  " 

.     IC. 

standard 
value   of   coal   see  page   27 


Knginee:ring  chemistry 


23 


14051 

i4CX)i 

13951 
I390I 

I385I 

1 380 1 

I375I 
I370I 

1 365 1 
I360I 

I355I 
I350I 

1 344 1 

I340I 
I335I 
I330I 
I325I 
1 320 1 

I3I5I 
I3IOI 

1 305 1 
I300I 
I295I 

1 290 1 

I285I 

1 280 1 

12751 

I270I 
1265 1 
1 260 1 

I255I 
I250I 
1245 1 

1 240 1 

I235I 
I230I 
1225 1 

1 2201 
I215I 

I2I0I 

1 205 1 
12001 
12000 


to  14100,  both  inclusive ic.  per  ton  below  standard 

to  14050  "  2C.    "      " 

to  14000  "  3c.    "     " 

to  13950  "  4c. 

to  13900  "  5c. 

to  13850  "  6c.    "     " 

to  13800  "  7c.    "     " 

to  13750  "  ....8c. 

to  13700  "  9c.    "     " 

to  13650  "  IOC.     "       " 

to  13600  "  lie. 

to  13550  "  I2C. 

to  13500  "  13c. 

to  13450  "  14c. 

to  13400  "  15c. 

to  13350  "  i6c. 

to  13300  "  17c.    " 

to  13250  "  i8c. 

to  13200  "  19c.    " 

to  13150  "  20c. 

to  I3IOO  "  2IC.     "       " 

to  13050  "  22c. 

to  13000  "  23c. 

to  12950  "  24c.    "     " 

to  12900  "  25c.    "  " 

to  12850  "  26c. 

to  12800  "  27c. 

to  12750  "  2Sc. 

to  12700  "  29c. 

to  12650  "  30c. 

to  12600  "  31C. 

to  12550  "  32c. 

to  12500  "  33^- 

to  12450  "  34c. 

to  12400  "  35c. 

to  12350  "  36c. 

to  12300  "  37c. 

to  12250  "  38c. 

to  12200  "  39c. 

to  12150  "  40c.    " 

to  I2IOO  "  4IC. 

to  12050  "  42c.    " 

and  below 43^. 


24 


ENGINEERING   CHEMISTRY 


Penalized  Coal. 

Coal  which  is  shown  by  analysis  to  contain  less  than  20  per  cent, 
of  volatile  matter;  9  per  cent,  of  ash;  or  1.50  per  cent,  of  sul- 
phur, will  be  accepted  without  a  deduction  from  the  bidder's 
price,  plus  or  minus  an  amount  for  excess  or  deficiency  of  B.  t.  u. 
value,  as  herein  provided.  Where  the  analysis  gives  amounts  for 
any  or  all  elements  in  excess  of  these  quantities,  deductions  will 
be  made  from  the  bidder's  price  in  accordance  with  the  tables  of 
values  of  volatile  matter,  ash  and  sulphur  below  given,  plus  or 
minus  the  amount  for  excess  or  deficiency  of  the  standard  B.  t.  u. 
value,  in  addition  to  any  other  deductions  which  may  be  made  as 
herein  provided. 

Table  of  Volatile  Matter. 


For  coal  which  is  found  by  test  to  contain  per  pound  of  dry  coal : 

Over  20  per  cent,  and  less  than  20.5  per  cent 2c.  per  ton 

20.5  per  cent,  and  over,  and  less  than  21.0  per  cent 4c.         " 


21.0 

21.5 
22.0 
22.5 
23.0 

23-5 
24.0 


21.5 
22.0 
22.5 
23.0 
23-5 
24.0 


6c. 

8c. 

IOC. 
I2C. 
14c. 

i6c. 

i8c. 


Table  of  Ash. 


For  coal  which  is  found  by  test  to  contain  per  pound  of  dry  coal : 

Over  9  per  cent,  and  less  than  9.5  per  cent 2c.  per 

9.5  per  cent,  and  over,  and  less  than  lo.o  per  cent 4c. 


ton 


lo.o 

10.5 

II.O 

11-5 
12.0 

12.5 
130 
13-5 


10.5 

II.O 

11.5 
12.0 

12.5 
130 
13-5 


6c. 

8c. 

IOC. 
I2C. 

14c. 

i6c. 
i8c. 
23c. 


ENGINEERING    CHEMISTRY  2^ 

Table  of  Sulphur. 

For  coal  which  is  found  by  test  to  contain  per  pound  of  dr}^  coal : 

Over  1.50  per  cent,  and  less  than  1.75  per  cent 6c.  per  ton 

1.75  per  cent,  and  over,  and  less  than  2.C0  per  cent loc.         " 

2.00        "  "  "  2.25         "         14c.         " 

2.25        "  "  "  2.50        "         i8c. 

2.50        "  "  20c.        " 

Should  any  lighter  of  coal  delivered  at  the  Company's  docks 
contain  less  than  700  tons,  a  deduction  of  7  cents  per  ton  will  be 
made  from  the  price  as  determined  by  the  B.  t.  u.  value  and 
analysis,  in  addition  to  any  other  penalty  provided  for  herein. 
Should  any  lighter  of  coal  delivered  at  the  Company's  docks  be 
rejected  by  the  Superintendent  on  account  of  excessive  amount 
of  coal  dust,  then  a  deduction  of  25  cents  per  ton  will  be  made 
from  the  price  as  determined  by  the  B.  t.  u.  value  and  analysis, 
for  the  coal  taken  from  said  lighter,  in  addition  to  any  other 
penalty  which  may  be  made  as  herein  provided.  Should  any 
lighter  of  coal  be  delivered  in  other  than  self-trimming  lighters 
as  herein  provided,  a  deduction  of  7  cents  per  ton  will  be  made 
from  the  price,  as  determined  by  the  B.  t.  u.  value  and  analysis, 
exclusive  of  any  other  penalty  which  may  be  made  as  herein 
provided. 

Weighing. 

The  Contractor's  Bill  of  Lading  will  be  checked  by  the  Com- 
pany's scales.  Should  there  be  a  deficiency  of  i  per  cent,  or 
more  between  the  bill  of  lading  and  the  Company's  weights,  then 
the  Company's  weights  will  be  taken  as  correct. 

The  following  is  a  convenient  form  for  recording  a  coal 
analysis : — 

Report  on  Coal  Analysis. 


26                              Kngine:e:ring  chemistry 
The  sample  of  coal  received  from  you 


,,  marked 


tests  as  follows : 

Per  cent. 

Moisture  in  coal  by  air-drying  24  hours  at  70°  F 

Moisture  in  air-dried  coal,  pulverized,  heated  Yz  hour  at  212°  F.    

Total  moisture    

Volatile  and  combustible  matter 

Fixed  carbon  

Sulphur   

Ash  

Total 

B.  t.  u.  per  pound 


As  above  stated,  after  the  determination  of  the  surface  moist- 
ure, the  coal  is  pulverized  in  an  Abbe  pulverizer  and  from  this 
a  portion  is  taken  for  the  determination  of  the  moisture  (at 
212°  F.),  the  volatile  and  combustible  matter,  fixed  carbon,  sul- 
phur and  ash,  the  result  being : 

Per  cent. 

Moisture   (at  212°  F.) 2.16 

Volatile  and  combustible  matter 8.56 

Fixed  carbon   77 ■'^1 

Sulphur    0.46 

Ash    11.55 


Total   , 100.00 

These  are  the  percentages  referred  to  coal  from  which  surface 
moisture  has  been  removed.  The  surface  moisture  in  this  case 
amounts  to  2.90  per  cent. ;  this,  if  added  to  the  above,  brings  the 
total  to  102.90  per  cent.  Hence  a  correction  is  necessary  for  the 
determinations:     This  is,  100  —  2.90  =  97.1  per  cent.,  so  that 


e:ngine:e:ring  chemistry  27 

each  of  the  above  determinations  (except  moisture,  air-dried) 
multiplied  by  the  factor  0.971  gives  the  following  percentages  on 
the  original  sample: 

Per  cent. 

Moisture,  by  air-drying    2.90 

Moisture  at  212°   F.  after  drying 2.10 

Total  moisture  5.00 

Volatile  and  combustible  matter 8.31 

Fixed  carbon   75-03 

Sulphur    0.44 

Ash    11.22 

Total    100.00 


Determination  of  the  "B.  t.  u."  in  Coal  by  Combustion 
in  Oxygen  Calorimeter. 

The  specifications  are  to  be  of  two  classes  (a)  and  (b).  The  pro- 
cedure specified  under  (a)  may  be  followed  in  tests  where  a  tolerance  of 
at  least  i  per  cent,  is  allowed.  The  procedure  under  (b)  is  to  be  used  in 
all  cases  where  the  Hmit  of  tolerance  is  less  than  i  per  cent,  and  is  to 
be  followed  in  all  cases  of  dispute.  Under  (b)  any  3  determinations 
made  at  the  same  time  on  the  same  sample  may  be  required  to  fall  within 
a  range  of  0.3  per  cent. 

Combustion  Bombs. — The  Atwater,  Emerson,  Mahler,  Peters,  Williams 
or  similar  bombs  may  be  used.  For  (a)  the  lining  material  of  the  bomb 
need  not  be  specified.  The  Parr  calorimeter  may  also  be  used,  but  only 
in  condition  that  both  parties  to  the  contract  agree  to  its  use.  For  (b) 
the  burnt  shell  has  a  lining  of  platinum,  gold,  porcelain,  enamel  or  other 
material  which  is  not  attacked  by  nitric  and  sulphuric  acids,  or  other 
products  of  combustion. 

Calorimeter  Jacket. — The  calorimeter  (except  the  Parr)  must  be  pro- 
vided with  a  water  jacket,  having  a  cover  to  protect  the  calorimeter  from 
air  currents.  The  jacket  must  be  kept  filled  with  water.  For  (b)  the 
water  in  the  jacket  must  be  kept  within  2  or  3°  C.  of  the  temperature 
of  the  room  and  should  be  stirred  continuously  by  some  mechanical 
stirring  device. 

Stirring  of  the  Calorimeter  Water. — The  water  in  the  calorimeter  must 
be  stirred  sufficiently  well  to  give  consistent  thermometer  readings  while 
the  temperature  is  rising  rapidly.  The  speed  of  stirring  should  be  kept  con- 
stant. For  (b)  a  motor  driven  screw  or  turbine  stirrer  is  recommended 
and  the  speed  should  not  be  sufficient  to  hold  the  temperature  of  the 


28  ENGINEERING    CHEMISTRY 

calorimeter  more  than  0.3  or  0.4°  C.  above  that  of  the  jacket,  when  the 
stirrer  is  allowed  to  run  continuously.  Accurate  results  cannot  be  ob- 
tained when  too  much  energy  is  supplied  by  the  stirring  device  or  when 
the  rate  of  stirring  is  too  irregular.  The  portion  of  the  stirring  device 
immersed  in  the  calorimeter  should  be  separated  from  that  outside  by 
non-conducting  material,  such  as  hard  rubber,  to  prevent  conduction  of 
heat  from  the  motor  or  outside  air. 

Thermometers. — Thermometers  used  shall  have  been  certified  by  a 
government  testing  bureau  and  shall  be  used  with  the  corrections  given 
on  the  certificate.  This  shall  also  appl}^  to  electrical  resistance  or  thermo- 
electric thermometers.  For  (b)  correction  shall  also  be  made  for  the 
temperature  of  the  emergent  stem  of  all  mercurial  thermometers,  and  for 
the  "setting"  of  Beckmann  thermometers.  For  accurate  work  either 
Beckmann  or  special  calorimetric  thermometers  graduated  to  o.oi  or  0.02° 
C.  are  required.  Such  thermometers  should  be  tapped  Hghtly  just  before 
each  reading  to  avoid  errors  due  to  the  sticking  of  the  mercury  meniscus, 
particularly,  when  the  temperature  is  falling.  A  convenient  method  is  to 
mount  a  small  electric  buzzer  directly  on  the  top  of  the  thermometer 
and  connect  it  up  with  a  dry  cell  and  a  push  button.  The  button  should 
be  pressed  for  a  few  seconds  immediately  before  each  reading. 

Oxygen. — Oxygen  used  for  combustions  shall  be  free  from  combustible 
material  and  for  (b)  it  shall  not  contain  more  than  5  per  cent,  nitrogen 
and  argon  together.  The  total  amount  of  oxygen  contained  in  the  bomb 
for  a  combustion  shall  not  be  less  than  5  grams  per  gram  of  coal.  But 
the  combustion  must  be  complete  as  shown  by  the  absence  of  any  sooty 
deposit  on  opening  the  bomb  after  firing. 

Firing  Wire. — The  coal  in  the  bomb  may  be  ignited  by  means  of  either 
iron  or  platinum  wire.  If  iron  wire  is  used,  it  should  be  of  about  No.  34 
B.  &  S.  gauge  and  not  more  than  10  centimeters  (preferably  5  centimeters) 
should  be  used  at  a  time.  A  correction  of  1,600  calories  per  gram  weight  of 
iron  wire  burned  is  to  be  subtracted  from  the  observed  number  of  calories. 
Except,  however,  that  this  correction  may  be  omitted  from  both  the 
standardizations  of  bomb  and  coal  combustions,  provided  the  same  amount 
of  wire  is  used  in  all  cases. 

Standardisation. — The  water  equivalent  of  a  calorimeter  can  best  be 
determined  by  the  use  of  the  standard  combustion  samples  supplied  by  the 
Bureau  of  Standards.  The  required  water  equivalent  is  equal  to  the 
weight  of  the  sample  multiplied  by  its  heat  of  combustion  per  gram  and 
divided  by  the  corrected  rise  in  temperature. 

The  calorimeter  shall  be  standardized  b}'  the  combustion  of  standard 
samples  supplied  by  the  Bureau  of  Standards,  and  used  according  to  the 
directions  given  in  the  certificates  which  accompany  them.  A  standardiza- 
tion shall  consist  of   a   series   of  not  less   than   5  combustions  of   either 


ENGINEERING    CHEMISTRY  29 

the  same,  or  different  standard  materials.  The  conditions  as  to  amount 
o£  water,  ox3-gen,  firing  wire,  method  of  correcting  for  radiation,  etc., 
under  which  these  combustions  are  made  shall  be  the  same  as  for  coal 
combustions.  For  (b)  in  the  case  of  any  disagreement  between  contract- 
ing parties  a  check  standardization  shall  be  made  at  the  time  of  test, 
but  such  standardization  may  consist  of  two  or  more  combustions  of 
standardizing  samples. 

Manipulation. 

1.  Preparation  of  Sample. — The  ground  sample,  which  is  in  approxi- 
mate moisture  equilibrium  with  the  atmosphere,  is  to  be  thoroughly 
mixed  in  the  bottle  and  an  amount,  approximately  i  gram,  is  to  be  taken 
out  and  weighed  in  the  crucible  in  which  it  is  to  be  burned.  Coals  which 
are  likely  to  be  blown  out  of  the  crucible  should  be  briquetted.  Standardiz- 
ing samples  are  also  to  be  briquetted.  After  w^eighing,  the  sample  should 
preferably  be  immediately  placed  in  the  bomb  and  this  closed.  This 
procedure  is  necessary  to  avoid  sublimation  when  naphthalene  is  used. 

2.  Preparation  of  the  Bomb. — The  firing  wire,  if  iron,  should  be  meas- 
ured and  coiled  in  a  small  spiral  and  connected  between  the  platinum 
terminals,  using,  if  necessary,  a  piece  of  platinum  wire  somewhat  heavier 
than  the  iron  wire,  to  make  the  connection.  The  platinum  and  the  iron 
must  both  be  clean.  x\bout  0.5  cc.  of  water  should  be  placed  in  the  bottom 
of  the  bomb  to  saturate,  with  moisture,  the  oxygen  used  for  combustion. 
When  the  crucible  is  put  in  place  in  the  bomb,  the  firing  wire  should 
touch  the  coal  or  briquette  of  standard  material.  For  the  combustion  of 
standardizing  samples  iron  wire  is  preferable  to  platinum. 

3.  Filling  the  Bomb  with  Oxygen. — Oxygen  from  the  supply  tank  is 
to  be  admitted  slowly  to  avoid  blowing  the  coal  from  the  crucible,  and 
the  pressure  allowed  to  reach  20  atmospheres  for  the  larger  bombs  or 
about  30  atmospheres  for  the  smaller  bombs,  so  that  the  bomb  shall 
contain  an  amount  of  oxygen  sufficient  for  complete  combustion,  namely, 
at  least  5  grams  per  gram  of  coal,  or  other  combustible.  When  feasible, 
the  bomb  may  be  exhausted  before  filling  to  remove  the  nitrogen  of  the 
air,  thus  reducing  the  amount  of  the  nitric  acid  formed. 

4.  Calorimeter  Water. — The  calorimeter  is  to  be  filled  with  the  required 
amount  of  water,  depending  upon  the  type  of  calorimeter.  The  amount 
may  be  determined  either  by  measurement  in  a  standardized  flask  or  by 
weighing.  For  {b)  distilled  water  should  be  used  and  the  amount  de- 
termined by  weighing.  The  amount  must  be  kept  the  same  as  that  used 
in  standardization  of  the  apparatus,  or  a  correction  applied  for  the  differ- 
ence in  weight. 

5.  Temperature  Adjustments. — The  initial  temperature  in  the  calori- 
meter should  be  so  adjusted  that  the  final  temperature  after  the  combus- 
tion, will  not  be  more  than  1°  C.  preferably  about  0.5°  C,  above  that  of 


30  e:ngine:e:ring  chemistry 

the  jacket,  under  which  conditions  the  total  correction  for  heat  gained 
from  or  lost  to  the  surroundings  will  be  small  when  the  rise  of  tempera- 
ture is  2  or  3°  C.  and  the  effect  of  evaporation  will  also  be  small. 

6.  Firing  Current. — The  electric  current  used  for  firing  the  charge 
should  be  obtained  from  storage,  or  dry  cells  having  an  electromotive 
force  of  not  more  than  12  volts.  The  circuit  should  be  closed  by  means 
of  a  switch  which  should  remain  closed  for  not  more  than  2  seconds.  When 
possible,  it  is  recommended  that  an  ammeter  be  used  in  the  firing  circuit 
to  indicate  when  the  firing  wire  has  burned  out.  For  {h)  the  electro- 
motive force  of  the  firing  battery  shall  not  exceed  12  volts,  since  a  higher 
voltage  is  liable  to  cause  an  arc  between  the  firing  terminals,  introducing 
additional  heat,  which  cannot  be  measured  with  certainty. 

7.  Method  of  Making  an  Observation. — The  bomb  when  ready  for 
firing,  is  to  be  placed  in  the  calorimeter,  the  firing  wires  connected,  the 
cover  put  in  place  and  the  stirrer  and  thermometer  so  placed  as  not  to 
be  in  contact  with  the  bomb  or  container.  The  stirrer  is  then  started  and 
after  the  thermometer  reading  has  become  steady,  not  less  than  2  minutes 
after  the  stirrer  is  started,  temperatures  are  read  at  i  minute  intervals  for 
5  minutes  and  the  charge  is  then  fired,  noting  the  exact  time  of  firing. 
Observations  of  temperature  are  then  made  at  intervals  depending  upon 
the  method  to  be  used  for  computing  the  cooling  correction.  When  the 
temperature  has  reached  its  maximum  and  is  falling  uniformly,  a  series 
of  thermometer  readings  is  taken  at  i  minute  intervals  for  5  minutes  to 
determine  the  cooling  rate. 

8.  Titration. — After  a  combustion  the  bomb  is  to  be  opened,  after 
allowing  the  gas  to  escape,  and  the  inside  examined  for  traces  of  un- 
burned  material  or  sooty  deposit.  If  these  are  found,  the  observations  shall 
be  discarded.  If  the  combustion  appears  complete,  the  bomb  is  to  be  rinsed 
out  and  the  washings  titrated  to  determine  the  amount  of  acid  formed. 
A  correction  of  230  calories  per  gram  of  nitric  acid  should  be  subtracted 
from  the  total  heat  observed.  If  the  sulphur  content  of  the  coal  is  de- 
termined, the  amount  of  sulphuric  acid  should  be  computed  and  an  addi- 
tional correction  of  1,220  calories  per  gram  of  H2SO4  should  be  sub- 
tracted, for  the  excess  of  the  heat  of  formation  of  the  sulphuric  acid  over 
that  of  nitric  acid. 

Computation  of  Rksui^ts. 

The  following  method  of  computation  is  recommended,  to  take  the 
place  of  the  Pfaundler  or  other  similar  formulas  for  computing  the  cool- 
ing correction  (radiation  correction). 

Observe  (i)  the  rate  of  rise  (n)  of  the  calorimeter  temperature  in 
degrees  per  minute  for  4  or  5  minutes  before  firing;  (2)  the  time  (a)  at 
which  the  last  temperature  reading  is  made  immediately  before  firing; 
(3)  the  time  (b)  when  the  rise  of  temperature  has  reached  six-tenths  of 


KNGINEERING   CHEMISTRY  3I 

its  total  amount  (this  point  can  generally  be  determined  by  adding 
to  the  temperature  observed  before  firing,  60  per  cent,  of  the  expected^ 
temperature  rise,  and  noting  the  time  when  this  point  is  reached)  ;  (4)  the 
time  (c)  of  a  thermometer  reading  taken  when  the  temperature  change 
has  become  uniform  some  5  minutes  after  firing,  (5)  the  final  rate  of 
cooling  (ro)  in  degrees  per  minute  for  5  minutes. 

The  rate  n  is  to  be  multiplied  by  the  time  b  —  a  in  minutes  and  tenths 
of  a  minute,  and  this  product  added  (subtracted  if  the  temperature  was 
falling  at  the  time  (a)  to  the  thermometer  reading  taken  at  the  time  a. 
The  rate  ^2  is  to  be  multiplied  by  the  time  c  —  b  and  this  product  added 
(subtracted  if  the  temperature  was  rising  at  the  time  c  and  later)  to  the 
thermometer  reading  taken  at  time  c.  The  difference  of  the  2  ther- 
mometer readings  thus  corrected,  provided  the  corrections  from  the  cer- 
tificate have  already  been  applied,  gives  the  total  rise  of  temperature  due 
to  the  combustion.  This  multiplied  by  the  water  equivalent  of  the 
calorimeter  gives  the  total  amount  of  heat  hberated.  This  result,  cor- 
rected for  the  heats  of  formation  of  nitric  and  sulphuric  acids  observed 
and  for  the  heat  of  combustion  of  the  firing  wire,  when  that  is  included, 
is  to  be  divided  by  the  weight  of  the  charge  to  find  the  heat  of  combustion 
in  calories  per  gram.  Calories  per  gram  multiplied  by  1.8  give  the  British 
thermal  units  per  pound.     (See  example.) 

The  results  should  be  reduced  to  calories  per  gram  or  British  thermal 
units  per  pound  of  dry  coal,  the  moisture  being  determined  upon  a  sample 
taken  from  the  bottle  at  about  the  same  time  as  the  combustion  sam,ple  is 
taken. 

For  an  accurate  comparison  of  coals  of  different  hydrogen  content, 
by  means  of  observation  with  the  combustion  bomb,  the  results  which 
are  obtained  at  constant  volume  should  be  reduced  to  heat  of  combustion 
at  constant  pressure,  and  to  "net"  instead  of  total  heat.  The  former 
reduction  is  usually  omitted  as  it  is  not  of  great  importance ;  the  latter 
is,  however,  of  considerable  importance  as  the  water  formed  by  the  com- 
bustion of  coal  in  the  bomb  is  all  condensed  and  its  latent  heat  measured, 
while  in  industrial  practice  the  water  usually  passes  off  uncondensed 
and   the   latent  heat  is    lost.     The   correction   for  water   condensed   may 

1  When  the  temperature  rise  is  not  approximately  known  beforehand,  it  is  only 
necessary  to  take  thermometer  readings  at  40,  50,  60  seconds  (and  possibly  70  seconds 
with  some  calorimeters)  after  firing,  and  from  these  observations  to  find  when  the  tem- 
perature rise  had  reached  60  per  cent,  of  the  total.  Thus,  if  the  temperature  at  firing  was 
2.135°,  at  40  seconds  3.05°,  at  50  seconds  3.92°,  at  60  seconds  4.16°,  and  the  final  temperature 
were  4.200°,  the  total  rise  was  2.07°  ;  60  per  cent,  of  it  was  1.44°.  The  temperature  to  be 
observed  was  then  2.07°  +  1.44°  =  3/05°.  Referring  to  the  observations  at  40  and  50 
seconds,  the  temperatures  were  respectively  3.05  and  3.92°.  The  time  corresponding  to 
the  temperature  of  3.51°  was  therefore 

^.Sl  —  "?  OS 

40  4-  -^ '-^-  X 10  =  45  seconds. 

40  +  3.92  -  3.05 


32  ENGINKERING    CHEMISTRY 

amount  to  nearly  5  per  cent,  for  some  bituminous  coals  while  for  anthra- 
cites and  coke  it  is  negligible. 

The  results  of  determinations  of  calorific  power  shall  be  stated  either 
as  "total"  heat  of  combustion  or  "net"  heat  of  combustion. 

Example. 
Observations. 
Water  equivalent  =  2550  grams 
Weight  of  charge  =  1.0535 
Approximate  rise  of  temperature  =  3.2° 
60  per  cent,  of  approximate  rise  =  1.9° 
Time  Temperature  Corrected  temperature 

10-21  15.244°   (Thermometer  corrections  from  the  certificate) 

22  .250 

23  .255 

24  .261 

25  .266 

(a)  26  .272  15.276° 

Charge  fired 

(b)  27-2       17.2°' 

(c)  31        18.500°  18.497° 

32  .498 

33  .497 

34  496 

35  .494 

36  .493 

Computation. 
Vx  =  0.028°  H-  5  =  0.0056°  per  minute;  b  —  a  =  1.2  minutes. 
The  corrected  initial  temperature  is 

15.276°  -r  0.0056°  X  1.2  =  15.283°. 
r^  =  0.007°  -^  5  =  0.0014°  per  minute ;  c  —  b  =1  3.8  minutes. 
The  corrected  final  temperature  is  18.497°  + 

0.0014  X   3-8   =  18.502° 

Total  rise  18.502°  —  15.283° =    3.219° 

Total  calories  2,550  X  3.219 =  8,209 

Titration,   etc =  — 7 

Calories  from  1.0535  grams  coal 8,202 

Calories  per  gram   7,785 

or  British  thermal  units  per  pound 14,013 

In  practice,  the  time  b  —  a  will  be  found  so  nearly  constant  for  a  given 
calorimeter  with  the  usual  amounts  of  fuel  that  b  need  be  determined  only 
occasionally. 


Enginee:ring  chemistry  33 

Ali.owabi,e  Variations. 

Per  cent. 

*^ame  analyst    0.3 

Different    analysts    0.4 

Total  heat  of  combustion  shall  refer  to  results  computed  as  described 
above. 

Net  heat  of  combustion  at  20°  shall  refer  to  results  computed  as 
follows :  The  amount  of  watef  in  grams  per  gram  of  coal  formed  by 
combustion,  multiplied  by  580  is  to  be  subtracted  from  the  "total"  heat 
in  calories  per  gram  to  give  the  "net"  heat  in  calories  per  gram,  or  the 
amount  of  water  in  pounds  per  pound  of  coal  multiplied  by  1,040  is  to 
be  subtracted  from  the  total  heat  in  British  thermal  units,  to  give  the 
net  heat  in  British  thermal  units,  per  pound. 

Combustion  oi?  Anthracites  and  Coke. 

For  anthracites  and  coke,  which  have  a  high  ash  content  and  do  not 
readily  burn  completely,  the  following  procedure  is  recommended : 

The  inside  of  the  crucible  is  lined  completely  wdth  ignited  asbestos  in 
a  thin  layer  pressed  well  down  into  the  angles.  The  coal  is  then  sprinkled 
evenly  over  the  surface  of  the  asbestos.  Otherwise  the  procedure  is  as 
previously  described. 

Parr  Cai,ori meter. 

The  essential  conditions  for  the  operation  of  the  Parr  or  peroxide 
calorimeter  are  as  follows  : 

The  coal  should  be  finely  pulverized.  While  6o-mesh  is  sufficient  for 
bituminous  coals,  anthracites  should  be  ground  to  at  least  lOO-mesh. 

The  sodium  peroxide  used  should  be  received  in  solder  sealed  tins 
and  of  a  size  suitable  for  emptying  completely  into  the  container  for  use, 
preferably  a  glass  jar  with  level  sealed  cap. 

In  addition  to  the  reaction  the  peroxide  serves  as  a  diluent  and  the 
ratio  necessary  for  a  quiet  reaction  should  be  maintained,  preferably 
0.5  gram  of  coal  to  approximately  10  grams  of  peroxide.  One  gram  of 
pulverized  potassium  chlorate  is  also  used  to  advantage.  A  thorough  and 
uniform  mixing  with  the  peroxide  is  secured  by  shaking  in  the  closed 
cartridge. 

Coals  with  moisture  above  2  or  3  per  cent,  must  be  oven-dried  at 
110°  C.  in  the  usual  manner  after  weighing  out,  and  before  mixing  with 
the  chemicals. 

The  correction  factors  to  be  subtracted  are  as  follows : 

1  The  initial  temperature  is  15.27°;  60  per  cent,  of  the  expected  rise  is  1.9°.  The  read- 
ing to  observe  is  then  17.2°. 

3 


34  ENGINEERING   CHEMISTRY 

Deg.  Cent. 

For  each  per  cent,  of  ash 0.00275 

For  each  per  cent,  of  sulphur 0.005 

For  I  gram  of  KCIO3 0.130 

For  electric  fuse  wire 0.008 

For  oxygen  of  bituminous  coals  for  0.5  gram 0.025 

For  oxygen  of  brown  Hgnites  for  0.5  gram 0.050 

For  oxygen  of  benzoic  acid  for  0.5  gram 0.124 

The  products  of  combustion,  CO2  and  H2O,  combine  with  the  chemical 
with  the  formation  of  heat,  which  amounts  in  each  case  to  27  per  cent,  of 
the  total  heat  of  the  reaction. 

The  corrections  for  ash,  fuse  wire,  etc.,  in  terms  of  the  temperature 
rise  together  with  radiation  and  thermometer  corrections  must  first  be 
subtracted  from  the  indicated  rise  in  temperature.  The  formula  for  the 
final  calculation  then  becomes  : 

Corrected  thermometer  rise  X  o-73  X  total  water  ,     .^        . 

^ — L2^^ =  calorific  value. 

0.5  g.  coal 


The  Emerson  Fuel  Calorimeter. 

The  scarcity  of  fuel,  and  the  continually  increasing  price,  have 
brought  about  conditions  which  reveal  the  fact  that  coal  can  no 
longer  be  bought  by  its  name  only,  such  as  "New  River"  or 
'Tocohontas,"  etc.,  as  in  nearly  every  district  where  the  high 
grade  coal  is  produced  there  are  seams  of  the  poorest  variety  of 
coal  within  a  few  miles  distance,  thus  making  the  buying  and 
selling  of  coal  from  the  district  name  only,  straightforward 
enough  from  the  sellers'  point  of  view,  but  possibly  misleading 
to  the  uninformed  buyer. 

The  agreement  between  the  seller  and  the  consumer  to  fix  the 
price  of  fuel  as  so  much  per  ton  for  a  fuel  giving  a  given  num- 
ber of  British  thermal  units  per  pound,  with  a  reduction  or  in- 
crease of  price  per  50  or  100  B.  t.  u.  less  or  more  than  the  speci- 
fied number  has  been  adopted,  and  is  at  present  operating  satis- 
factorily among  users  of  coal  in  large  quantities. 

The  buying  of  fuel  on  a  guarantee  to  reach  or  excel  a  certain 
specified  British  thermal  units  per  pound  is  adopted  in  some  in- 
stances, and  gives  very  satisfactory  results. 

The  fuel  calorimeter  here  described  is  the  so-called  bomb  calo- 


ENGINKERING    CIIICMISTRY 


35 


36  ENGINEKRING   CHEMISTRY 

rimeter  of  the  Berthelot  type,  meaning  that  the  combustible  dur- 
ing ignition  is  retained  in  a  stout  receptacle  in  which  is  inserted 
an  excess  of  oxygen  gas  under  pressure  to  carry  on  the  combus- 
tion. The  determination  of  the  heat  of  combustion  is  made  by  a 
calorimeter  method,  the  bomb  being  placed  in  a  watei  calorim- 
eter during  the  combustion.  The  product  of  the  rise  in  tem- 
perature in  the  calorimeter  and  the  water  plus  the  water  equiv- 
alent of  the  calorimeter  and  its  contents  gives  us  directly  the 
quantity  of  heat  in  calories  per  given  weight  of  combustible. 
The  combustible  is  ignited  by  means  of  a  fine  platinum  wire 
rendered  incandescent  by  the  passage  of  an  electric  current. 
One  terminal  of  the  circuit  is  introduced  into  the  interior  by 
means  of  an  insulated  plug,  the  other  terminal  is  grounded  in 
the  bomb. 

The  combustible  is  introduced  in  a  finely  divided  condition  to 
insure  complete  combustion,  and  is  held  by  a  pan  on  a  wire  sup- 
port. 

Apparatus. 

Bomb. — The  bomb  is  made  of  carbon  steel,  consisting  of  two 
cups  joined  by  means  of  a  heavy  steel  nut.  The  two  cups  are 
machined  at  their  contact  faces  with  a  tongue  and  groove,  the 
joint  being  made  tight  by  means  of  a  lead  gasket  inserted  in  the 
groove.  The  lining  is  of  sheet  nickel,  spun  in  to  fit,  or  of  a 
double  process  high  temperature  porcelain.  The  bomb  is  made 
up  tight  with  a  milled  wrench  or  spanner.  The  oxygen  valve 
at  the  top  of  the  bomb  is  made  of  steel.  The  pan  holding  the 
combustible  is  of  platinum,  and  the  supporting  wire  of  nickel. 
The  fuse  wire  should  be  platinum. 

Calorimeter. — The  jacket  is  a  double-walled  copper  tank  be- 
tween the  walls  of  which  water  is  inserted.  The  calorimeter  is 
made  as  light  as  possible,  of  sheet  brass. 

Stirring  Device. — The  stirrer  is  directly  connected  to  a  small 
series  motor  and  is  enclosed  in  a  tube  to  facilitate  its  action  in  cir- 
culating the  water.  The  stirrer  is  mounted  on  a  post  on  the 
calorimeter  jacket  as  is  the  thermometer  holder. 


^B 


Fig.   3. 


38  i:ngine:e:ring  che:mistry 

The  motor  is  driven  by  a  iio-volt  circuit,  and  should  be  placed 
in  series  with  a  i6-candle-power  lamp.  (55  watts,  taking  y^  am- 
pere.) If  so  desired,  a  motor  driven  by  a  battery  can  be  speci- 
fied in  ordering  the  apparatus. 

Oxygen  Piping. — The  piping  for  the  insertion  of  oxygen  under 
pressure  is  made  especially  strong  and  durable.  The  piping  of 
small  internal  bore  is  made  of  heavy  brass.  The  system  is  fitted 
with  a  hand  nipple  at  one  end  to  make  the  connection  with  the 
bomb,  and  the  other  end  has  a  special  fitting  to  grasp  the  oxygen 
supply  tank. 

Immediately  after  each  run  the  inside  of  the  bomb  should  be 
washed  out  with  a  cloth  moistened  with  a  dilute  solution  of 
caustic  soda  and  then  with  water. 

The  linings  should  be  frequently  removed  and  the  inner  sur- 
face of  the  bomb  under  the  linings  should  be  coated  slightly  with 
oil.  (This  oil  will  in  no  way  affect  the  operation  of  the  bomb 
and  can  be  left  when  the  same  is  in  operation.) 

The  bomb  is  of  steel  and  plated  with  nickel.  This  plating 
cannot  be  made  an  absolute  protection  against  corrosion  being 
placed  as  it  is  directly  upon  the  steel  and  care  should  be  taken 
that  the  entire  surface  should  be  covered  with  a  slight  film  of  oil 
after  using  the  apparatus. 

MANIPUI.AT10N. 

Heat  of  Combustion  of  Solid  fuels. — Place  the  lower  half  of 
the  bomb  in  the  holder  and  the  platinum  pan  in  the  wire  support 
after  having  wired  the  fuse,  wire  according  to  the  accompany- 
ing sketch  and  following  directions. 

To  place  the  platinum  wire,  twist  one  end  of  the  same  into 
the  small  hole  at  edge  of  pan  and  extend  the  wire  across  the  pan 
through  the  hole  in  mica,  allowing  it  to  dip  sufficiently  to  be  in 
contact  with  the  fuel  which  is  afterward  placed  in  the  pan. 
After  passing  through  the  mica,  the  wire  is  led  to  the  side  of 
bomb,  where  it  is  grounded  at  the  binding  post.  The  wire  must 
in  no  case  touch  the  pan  except  at  the  edge  where  the  twisted 
contact  is  made.    The  fuse  wire  should  be  placed  in  series  with 


e:ngine:e:ring  chemistry 


39 


two  32  candle-power  lamps  in  parallel  when  no- volt  power 
circuit  is  used  for  firing. 

The  fuel  used  is  sampled,  crushed,  and  powdered  according 
to  directions  given  below. 

Fill  a  test-tube  or  convenient  weighing  vial  with  the  prepared 
sample  and  weigh  the  same  accurately  to  ^/^^  of  a  milli- 
gram. Pour  from  this  into  the  pan  in  the  bomb  until  the  pan 
is  approximately  half  full.  Weigh  the  vial  again  and  the  dif- 
ference of  the  above  weighing  gives  the  net  quantity  of  fuel  in 
the  bomb.  This  weight  should  be  greater  than  ^/^^  of  a  gram, 
and  not  more  than  iVio  grams.  For  hard  coal  the  maximum 
charge  should  be  not  greater  than  i  gram.  Hard  coal  should  not 
be  as  finely  divided  as  soft  coal.  (Through  an  80-mesh  sieve  is 
sufficient.) 


JJTtca^ 


JPlatinum, 


Fig.  4. 


The  upper  half  of  the  bomb  is  placed  in  position  and  the  nut 
screwed  down  as  far  as  may  be  by  hand,  care  being  taken  not 
to  cross  the  threads.  The  shoulder  on  the  upper  half  of  the  bomb 
over  which  the  nut  makes  bearing  contact  should  be  thoroughly 
lubricated  with  graphite  and  oil.  Extreme  care  should  be  taken 
that  no  oil  or  grease  is  deposited  on  the  lead  gasket,  as  the  bomb, 
when  working  properly,  closes  without  the  upper  half  turning 
on  the  gasket  on  account  of  the  contact  friction  of  the  nut.  Any 
oil  on  the  lead  gasket  would  tend  to  hinder  the  proper  action  in 
this  respect. 


40  ENGINEERING   CHEMISTRY 

The  large  wrench  is  used  to  make  the  joint  tight. 

The  bomb  is  now  ready  to  be  filled  with  oxygen,  and  this  is 
accomplished  by  means  of  the  spindle  valve  at  the  top  of  the 
bomb.  The  nipple  is  coupled  to  the  oxygen  piping  by  means  of 
the  attached  hand  union.  In  handling  the  bomb,  care  should  be 
taken  not  to  tip  or  jar  the  same,  as  fuel  may  be  thrown  from  the 
pan. 

The  spindle  valve  on  the  bomb  need  only  be  opened  one  turn, 
and  then  the  valve  on  the  oxygen  supply  tank  is  very  cautiously 
opened.  The  pressure  gauge  should  be  carefully  watched  and 
the  tank  valve  so  regulated  that  the  pressure  in  the  system  shall 
rise  very  gradually.  When  the  pressure  reaches  300  pounds  per 
square  inch,  the  tank  valve  is  closed,  and  then  the  spindle  valve 
immediately  after. 

The  bomb  should  be  immersed  in  water  immediately  to  detect 
any  possible  leakages.  (Preferably  a  glass  jar,  as  slight  leaks 
are  detected  by  looking  from  the  various  sides.) 

The  bomb  is  now  ready  for  the  calorimeter,  which  is  prepared 
as  follows : 

Nineteen  hundred  grams  of  distilled  water  are  placed  in 
the  calorimeter  can  at  a  temperature  about  i^°  below  the 
jacket  temperature  (which  temperature  should  h&  approximately 
of  the  room  temperature).  The  bomb  is  then  placed  in  the 
calorimeter  and  the  stirrer  and  thermometer  are  lowered  into 
position  as  indicated  by  the  preceding  illustration.  The  ther- 
mometer is  immersed  about  3  inches  in  the  water.  The  bulb  of 
the  thermometer  should  not  touch  the  bomb. 

The  terminals  of  the  electric  circuit  used  for  firing  should  now 
be  attached,  one  to  the  bomb  and  the  other  to  the  can ;  this  latter 
making  contact  with  the  pin  in  the  plug  at  the  bottom  of  the 
bomb.  Care  should  be  taken  that  the  bomb  does  not  touch  the 
sides  of  the  can. 

The  Operation. 

The  stirrer  is  now  started,  and  allowed  to  run  3  or  4  minutes 
to  equalize  the  temperature  throughout  the  calorimeter. 

Readings  of  the  thermometer  are  now  taken   for  5  minutes 


ENGINEERING    CHEMISTRY  4I 

(reading  to  the  i-iooth  degree  every  ^  minute)  at  the  end 
of  which  time  the  switch  is  turned  on  for  an  instant  only ;  which 
will  be  found  sufficient  to  fire  the  charge.  In  course  of  a  few 
seconds  the  temperature  begins  to  rise  rapidly  and  readings  are 
taken  as  before,  every  half  minute  from  the  time  of  firing.  Af- 
ter a  maximum  temperature  is  reached  and  the  rate  of  change  of 
temperature  is  evidently  due  only  to  the  radiation  to  or  from  the 
calorimeter,  we  then  continue  our  readings  for  an  additional  5 
minutes,  reading  every  j^^  minute.  These  readings  before  the 
firing  and  after  the  maximum  temperatures  are  necessary  in  the 
computation  of  the  cooling  correction.  The  time  elapsed  from 
the  time  of  firing  to  the  maximum  temperature  should  be  in  no 
case  more  than  6  minutes. 

When  through  with  run,  replace  bomb  in  the  holder  and  allow 
the  products  of  combustion  from  within  to  escape  through  the 
valve  at  the  top  of  the  bomb.  Unscrew  the  large  nut  and  clean 
the  interior  of  the  bomb.  The  inside  of  the  nut  should  be  kept 
greased;  and  also  the  threaded  part  at  the  top  of  the  lower  cup. 

The  pan  may  be  cleaned  by  boiling  in  dilute  hydrochloric  acid. 
Any  slag  clinging  to  the  pan  may  be  fused  with  sodium  car- 
bonate.   The  fused  mass  dissolves  in  hot  water. 

Computation. 
The  data  obtained  during  the  run  is  used  as  follows : 
The  difference  between  the  temperature  at  maximum  and  the 
temperature  at   firing  gives  directly  the  apparent   rise  in  tem- 
perature in  the  calorimeter.    To  this  apparent  rise,  however,  we 
must  apply  a  cooling  correction  which  is  computed  as  follows : 

The  change  in  temperature  during  the  preliminary  5  minutes 
of  reading  divided  by  the  time  (5  minutes)  gives  the  rate  of 
change  of  temperature  per  minute  due  to  radiation  to  or  from 
the  calorimeter  and  also  any  heating  due  to  stirring,  etc.  This 
factor  is  called  Rj,  in  like  manner  the  readings  taken  after  final 
temperature  give  Ro.  These  two  rates  of  change  of  temperature 
also  give  the  existing  conditions  in  the  calorimeter  at  the  start 
and  at  the  finish  of  the  run.  Therefore,  the  algebraic  sum  of 
the  two  rates  divided  by  two  will  give  the  mean   (or  average) 


42  ENGINEERING   CHEMISTRY 

value  of  the  rate  of  change  of  temperature  during  the  entire  run 
due  to  radiations  to  and  from  the  calorimeter.  This  value  mul- 
tiplied by  the  time  from  firing  to  maximum  will  give  the  total 
cooling  correction.  The  cooling  correction  thus  determined  has 
been  found  by  long  experience  to  be  a  very  close  approximation 
to  the  radiation  effects  encountered  when  working  under  these 
above  conditions. 

This  latter  quantity  is  either  added  to  or  subtracted  from  the 
apparent  rise  taken  from  the  data  of  the  run,  accordingly  as  the 
balance  of  heat  radiation  is  to  the  surroundings  or  from  the 
surroundings.  This  is  at  once  determined  from  an  inspection 
of  the  data. 

Cooling  correction  is  expressed : 

R,  ±  R, 
X  time  from  firing  to  maximum. 

The  correction  rise  of  temperature  divided  by  the  weight  of 
fuel  used  will  give  the  rise  per  gram  of  fuel. 

This  rise  per  gram  times  the  weight  of  water  plus  "water 
equivalent"  will  give  immediately  the  calories  per  gram  of  fuel, 
which  is  the  result  to  be  obtained.  The  result  in  calories  per 
gram  of  fuel  multiplied  by  the  factor  1.8  gives  the  B.  t.  u.  per 
pound  of  fuel. 

The  water  equivalent  is  the  quantity  of  heat  necessary  to  raise 
the  metal  parts  of  the  calorimeter  and  the  bomb  1°  C.  and  is 
equal  to  the  sum  of  the  product  of  their  weights  times  their 
specific  heats. 

This  water  equivalent  factor  may  be  checked  by  burning  in 
the  bomb  a  fuel  or  combustible  of  standard  heating  value,  the 
same  having  been  determined  accurately.  Extreme  care  should 
be  taken  that  such  standardizing  substances  should  be  of  prac- 
tically 100  per  cent,  purity  and  absolutely  free  from  chemically 
or  physically  combined  water. 

The  value  of  such  a  standard  substance  in  calories  per  gram 
is  divided  by  the  rise  in  temperature  in  the  calorimeter  per 
gram  of  sample  and  the  result  is  the  water  plus  the  water  equiva- 


ENGINKE^RING    CHE:mISTRY  '        43 

lent  of  the  apparatus.    The  water  being  known,  the  water  equiva- 
lent is  thus  determined. 

With  a  combustible  of  absolute  purity  this  determination  will 
check  the  value  of  the  water  equivalent  as  figured  from  the 
weights  and  specific  heats  of  the  material  included  in  the  acting 
parts  of  the  calorimeter. 

Heavy  Oils,  Coke,  Hard  Coal,  Etc. — The  determination  of  the 
heat  of  combustion  of  heavy  oils  such  as  crude  petroleum,  and 
also  of  coke  and  extremely  hard  coals  is  best  made  by  burning 
the  same  mixed  with  a  ready  burning  combustible,  such  as  a 
high-grade  bituminous  coal  or  C.  P.  carbon.  This  auxiliary  com- 
bustible facilitates  the  complete  combustion  of  the  whole  mixture 
in  the  case  of  coke  and  hard  coal  and  with  the  heavy  oil  it  acts 
as  a  holder  and  prevents  rapid  evaporation  of  the  oil. 

The  auxiliary  combustible  should  be  placed  at  the  bottom  of 
the  pan  and  the  coke,  coal  or  oil  sprinkled  over  it.  The  C.  P. 
carbon  or  other  auxiliary  combustible  should  be  dried  with 
extreme  care  and  carefully  standardized  as  to  the  resulting  rise 
in  temperature  per  gram  in  the  calorimeter  when  the  same  is 
completely  burned. 

Fu^I.  TESTING. 

Sampling. — The  sampling  is  a  most  important  element  in  the 
process  of  the  determination  of  the  heating  value  of  a  fuel.  The 
rules  which  are  stated  below  should  be  used  with  due  considera- 
tion and  judgment. 

The  working  conditions  under  which  the  fuel  has  to  be 
sampled  vary  widely.  For  instance,  the  large  coal  pile  of  10,000 
tons,  the  shipment  of  20  or  30  carloads,  the  whole  mine,  or  a 
few  tons  may  be  the  subject  of  test  at  hand  and  the  method  of 
sampling  is  slightly  different  in  each  case.  If  sampling  is  to  be 
done  at  the  mine,  from  a  map  of  the  mine  several  points  for 
samples  should  be  chosen  in  such  manner  as  to  give  a  fair  sample 
of  the  whole.  These  points  should  be  near  the  working  face. 
A  cut  across  the  face  from  3  to  6  inches  in  width  and  i  inch  in 
thickness  should  be  made  at  each  point.     This   cut  should  be 


44  ENGINKERING    CHEMISTRY 

taken  out  complete  except  for  that  part  which  would  be  rejected 
by  the  mine  worker. 

The  samples  taken  from  these  several  points  should  be  thrown 
together,  crushed  and  mixed.  The  crushing  should  bring  the 
size  down  to  about  3/2 -inch  cubes  or  less. 

The  sample  thus  procured  is  spread  out  on  an  oilcloth  or 
canvas  and  mixed.  Then  by  drawing  lines  through  the  sample 
at  right  angles  the  fuel  is  systematically  reduced  in  bulk  and  at 
the  same  time  sampled  by  the  usual  process  known  as  "quarter- 
ing," that  is,  the  opposite  quarters  are  taken  out  and  the  rest 
discarded.  The  sample  taken  away  from  the  mine  need  not 
exceed  that  which  may  be  contained  in  an  ordinary  2-quart  jar. 

This  2-quart  sample  is  ground  to  a  smaller  size  either  with 
heavy  mortar  and  pestle  or  proper  grinding  machine  and  then 
spread  on  a  clean  surface  of  glazed  paper  or  cloth  and  after 
mixing  the  quartering  is  repeated.  Regrinding  and  quartering 
are  repeated  until  the  sample  is  reduced  to  about  100  cc.  This 
sample  is  finely  powdered  and  the  whole  passed  completely 
through  a  lOO-mesh  sieve.  This  finely  powdered  sample  is  spread 
on  a  glazed  paper  and  quartered  for  a  small  sample  for  the 
weighing  tube  (5  or  6  grams).  The  remainder  should  be  tightly 
sealed  and  kept  for  future  reference. 

If  sampling  is  attempted  on  a  large  pile,  say  one  of  10,000 
tons  or  like,  a  grab  sample  with  shovel  if  made  with  due  care 
and  judgment  gives  accurate  results.  Shovelfuls  should  be  taken 
at  intervals  from  the  base  of  the  pile  to  the  top,  and  should  be 
taken  18  inches  or  2  feet  under  the  surface  of  the  pile  if  the 
pile  has  been  long  exposed  to  the  weather.  A  considerable  part 
of  the  sample  should  be  taken  from  the  larger  pieces  which  are 
invariably  found  at  the  bottom  of  the  pile.  Any  pieces  which 
are  too  large  to  be  handled  with  the  shovel  should  be  broken 
with  a  maul  and  parts  of  the  fragments  used  for  sample.  Pieces 
which  are  often  encountered  containing  practically  nothing  but 
slate  or  other  forms  of  rock  should  not  be  entirely  neglected,  and 
it  is  herein  that  the  whole  operation  relies  on  the  judgment  of 
the  sampler.    It  is  purely  a  matter  of  observation  of  the  apparent 


e:ngine:e:ring  chemistry  45 

percentage  of  such  material  present  in  the  pile  that  governs  the 
sampler  as  to  how  much  he  shall  include  of  the  same  in  his 
sample.  His  ability  to  accomplish  the  above  determines  the  suc- 
cess or  failure  of  his  work. 

The  total  sample  taken  from  a  pile  need  not  exceed  an  amount 
which  may  be  contained  in  a  box  3  feet  on  a  side.  This  sample 
is  crushed,  ground,  mixed  and  quartered  as  was  described  above. 

If  sample  is  to  be  procured  from  carload  shipment  a  few  well 
chosen  shovelfuls  from  each  car  give  the  desired  results : 

Sampling  from  shipment  from  vessels  is  accomplished  by  tak- 
ing a  grab  sample  from  the  hold  of  the  ship  or  by  having  the 
stokers  instructed  to  lay  aside  a  shovelful,  at  certain  intervals  in 
their  work  of  filling  the  bucket  hoists. 

Sampling  from  boiler  tests  is  accomplished  by  saving  an  aver- 
age shovelful  from  each  stoke  period  by  the  fireman. 

The  same  rules  and  machines  which  are  used  in  the  sampling 
of  ore  are  equally  good  in  the  sampling  of  fuel. 

Moisture:. 

If  the  moisture  is  to  be  determined  a  quartered  sample  may  be 
placed  on  a  dried  and  weighed  watch  glass,  and  the  weights  taken 
before  and  after  heating  in  the  drying  closet.  When  removing 
watch  glass  from  closet  it  should  be  cooled  in  a  desiccator.  The 
temperature  of  the  drying  closet  should  be  approximately  105°  C. 
and  the  sample  should  be  kept  in  the  closet  not  less  than  40 
minutes. 

SAMPLE  RUN. 

Sample  No.  128  (dried). 

Run  No.  2. 

Thermometer  used,  No.  11,258. 

Weight  of  tube  and  coal  =:  7.8047  grams 

Weight  of  tube  =  7.0742  grams 


Coal  taken  =  0.7305  gram 

Weight  of  water  =  2,000  grams 


46 


ENGINEERING   CHEMISTRY 


Readings  of  Thermometer. 


Time 

Temp. 

Time 

Temp. 

Time 

Temp. 

O.O 

19.300 

0.30 

20.050 

11.00 

21.695 

0.30 

19.300 

6.00 

21.050 

0.30 

21.695 

1. 00 

19.300 

0.30 

21.420 

12,00 

21.690 

0.30 

19-305 

7.00 

21.570 

0.30 

21.690 

2.CX3 

19-305 

0.30 

21.650 

13.00 

21.690 

0.30 

19.310 

8.00 

21.690 

0.20 

21.690 

3.00 

19.310 

0.30 

21.700  Max. 
Temp. 

0.30 

19-315 

9.00 

21.700 

4.00 

19.320 

0.30 

21.700 

0.30 

19.320 

10.00 

21.700 

5-00 

19.325  Firing 
Temp. 

0.30 

21.700 

0.002 


Apparent  rise  in  temperature  =  2.375. 

Rate  of  change  of  temperature  before  firing  =  0.005  =  Ri- 

Rate  of  change  of  temperature  after  maximum  temperature 

=  R2. 
Average  rate  of  change  of  temperature  during  run  =  0.0015. 
Total  cooHng  correction  :=  [0.0015  X  3-5  (min.)]  =  0.005  [subtractive]. 
Total  corrected  rise  in  temperature  =  2.370. 
Rise  per  gram  of  sample  =  3.244. 

The  water  equivalent  of  bomb,  calorimeter  can,  stirrer,  etc.  =r  434. 
Gram  calories  per  gram  of  sample  =  (2,000  +  434)  X  3.244  =  7,895. 
British  thermal  units  per  pound  of  sample  ==  7,895  X  I-8  =  14,310. 


GOVERNMENT  SPECIFICATIONS  FOR  PURCHASE  OF  COAL. 


Anthracite  Coal. 

Price  and  Payment. 
Payment  will  be  made  at  the  price  named  in  the  proposal   for  the 
coal  specified,  corrected  as  indicated  in  Table  IVa  for  variations  in  ash 
above  and  below  the  standard,  as  shown  by  analysis. 

Bituminous  Coal. 

Price  and  Payment. 
On  certification  from  the  coal-inspection  section  of  the  United  States 
Geological  Survey  that  samples  have  been  procured  from  deliveries  con- 
stituting a  completed  order,  payment  will  be  made  at  once  of  90  per  cent, 
of  the  amount  of  the  bill,  10  per  cent,  being  withheld  to  protect  the  Gov- 
ernment against  the  delivery  of  coal  of  inferior  quality  and  to  offset  any 
deduction  that  may  be  determined  by  the  United  States  Geological  Survey 


ENGINKKRING    CHEMISTRY 


47 


from  the  average  quality  of  all  the  deliveries  on  the  order.  On  receipt  of 
the  Survey's  report  on  the  quality  of  the  coal  final  settlement  will  be 
made. 

TABIvE  IVa. — Price  Corrections,  in  Cents  per  Ton,  for  Anthracite 

CoAE,  Due  to  Variations  in  Ash  in  "Dry  Coae"  Above 

and  Beeow  the  Established  Standard. 


size  of  coal 

Ash  in  "dry  coal"  per  cent. 

Furnace 
and  egg 

stove 

Chestnut 

Pea 

Buckwheat 

6. ox  to    6.50 
6.51  to    7.00 
7.01  to    7.50 
7.51  to    8.00 

24 
21 
18 
15 

27 

24 
21 
18 
15 

27 

24 
21 
18 
15 

15 

12.5 
10 

7.5 
5 

8.01  to    8.50 
8.51  to    9.00 
9.01  to    9.50 
9.51  to  10.00 

Contract 
price 

10.01  to  10.50 
10.51  to  11.00 
ii.oi  to  11.50 
11.51  to  12.00 

Contract 
price 

12.01  to  12.50 
12.51  to  13.00 
13.01  to  13.50 
13.51  to  14.00 

15 
18 
21 
24 

Contract 
price 

14.01  to  14.50 
14.51  to  15.00 
15.01  to  15.50 
15.51  to  16.00 

15 
18 
21 
24 
27 

Contract 
price 

12 
10 

8 

16.01  to  16.50 
16.51  to  17.00 

15 
18 

21 

24 
27 

6 

4 

17.01  to  17.50 
17.51  to  18.00 
18.01  to  18.50 
18.51  to  19.00 

5-0 

7-5 
10. 0 

12.5 
15.0 

Contract 
price 

19.01  to  19.50 
19.51  to  20.00 
20.01  to  20.50 
20.51  to  21.00 
21.01  to  21.50 
21.51   to  22.00 

4 

8 

14 
21 

32 

48 

Note. — Figures  above  heavy  line  represent  cents  per  ton  to  be  added  to  contract 
price;  figures  below  heavy  line  represent  cents  per  ton  to  be  deducted  from  contract 
price. 

If  the  10  per  cent,  withheld  should  prove  insufficient  to  satisfy  the 
claim  of  the  Government  on  account  of  the  delivery  of  fuel  of  low  grade, 
the  balance  shall  be  deducted  from  the  next  succeeding  order  or  orders. 


48 


i:ngine:e:ring  chemistry 


Payment  will  be  made  at  the  price  named  in  the  proposal  for  the 
coal  specified  therein,  corrected  for  variations  in  heating  value  and  ash, 
as  shown  by  analysis,  above  and  below  the  standard  established  by  the 
contractor  in  his  proposal. 

The  correction  in  price  for  variations  in  British  thermal  units  is  a 
pro  rata  one  and  is  determined  by  the  following  formula : 

Delivered  B.  t.  u.  ^  .         ^       ,       .  •      .    u        -j 

5 — ;— r; X  contract  price  =  price  to  be  paid. 

Standard  B.  t.  u.    "^  ^  ^  ^ 

For  example,  if  a  coal  delivered  on  a  contract  guaranteeing  14,000 
B.  t,  u.  in  coal  "as  received"  at  a  price  of  $3  per  ton  shows  by  calorific 
test  14,300  B.  t.  u.  in  coal  "as  received,"  the  price  to  be  paid  is  found,  by 
substitution  in  the  formula,  to  be 


14,300 


X  |3  =  $3,064. 


14,000 

The  price  will  also  be  further  corrected  for  the  percentage  of  ash. 
For  all  coal  which  by  analysis  contains  less  ash  than  that  established  in 
this  proposal  a  premium  of  i  cent^  per  ton  for  each  whole  per  cent,  less 
ash  will  be  paid,  x^n  increase  in  the  ash  content  of  2  per  cent,  over  the 
standard  established  by  contractor  w-ill  be  tolerated  without  deduction. 

Price  Corrections,  in  Cents  Per  Ton,  for  Bituminous  Coal,  Due 

TO  Variations  in  Ash  in  "Dry  Coal"  Above  and  Below 

THE  Established  Standard. 


Contract  stan- 
dard, per  cent 
of  ash  in 
"dry  coal" 


Maximum 

limit 

for  ash 

(per  cent.) 


Schedule  of  variations  in  ash  (percent.) 


Below- 


Higher  limits 


5 
6 

7 
8 

9 
10 
II 
12 
13 
14 
15 
16 

17 
18 


12 
13 
14 
14 
15 
16 
16 

17 
18 

19 
19 
20 
21 
22 


7 
8 

9 
10 
II 
12 
13 
14 
15 
16 

i7 

18 

19 
20 


Deduction  ( cts . per  ton ) 


7-8 
8-9 
9-10 

lO-II 

11-12 
12-13 
13-14 
14-1S 
15-16 
16-17 
17-18 
18-19 
19-20 
20-21 


8-9 
9-10 
10- 1 1 
11-12 
12-13 
13-14 
14-15 
15-16 
16-17 
17-18 
18-19 
19-20 
20-21 
21-22 


9-10 

lO-II 
II-I2 
12-13 
13-14 
14-15 
15-16 
J6-I7 
17-18 
18-19 
19-20 
20-21 
21-22 
22-23 


10-11 
11-12 
12-13 
I3-H 
14-15 
15-16 
16-17 
17-18 
18-19 
19-20 
20-2 1 
21-22 
22-23 


12 


II-I2 
12-13 
13-14 

14-^5 

15-16 
16-17 
i7-:8 
18-19 
19-20 
20-21 
21-22 
22-23 


18 


12-13 
13-H 
14-15 
15-16 
16-17 
17-18 
18-19 
19-20 
20-21 
21-22 


25 


13-14 
14-15 
15-16 
16-17 
17-18 


35 


In  the  specifications  for  the  fiscal  1910-11  this  premium  will  be  2  cents. 


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50  e:ngine:e:ring  che:mistry 

.     VALUE  OF  COAL  AS  FUEL.* 


Requirements  of  Use. 

Coal  is  now  burned  for  power  production  in  gas  producers  and  in 
boiler  furnaces.  For  coals  and  lignites  high  in  moisture  or  high  in  ash, 
the  gas  producer,  used  in  connection  with  a  gas  engine,  is  best  adapted 
to  develop  power,  but  for  the  generation  of  steam,  which  can  be  used 
for  heating  as  well  as  for  power,  coal  may  be  more  conveniently  burned 
in  a  specially  constructed  furnace  under  a  boiler. 

Coal  is  burned  under  boilers  for  producing  power,  for  drying  various 
materials,  or  for  warming  buildings.  The  most  valuable  coal,  therefore, 
is  that  which  gives  up  the  most  heat  to  the  boiler  for  a  given  weight 
burned. 

The  value  of  a  coal  is  indicated  by  the  number  of  heat  units  it  con- 
tains. This  heating  value  is  expressed  in  terms  of  British  thermal  units 
(abbreviated  B.  t.  u.)  per  pound  of  coal,  and  is  determined  by  means  of  a 
special  apparatus  called  a  calorimeter. 

In  purchasing  coal  for  any  power  plant  the  aim  should  be  to  obtain  a 
fuel  which,  all  things  considered  (such  as  equipment,  price  of  coal,  and 
cost  of  labor  and  repairs),  will  produce  horse-power  for  the  least  cost. 
Experiments  seem  to  indicate  that  almost  any  fuel  may  be  burned  with 
reasonable  efficiency  in  a  properly  designed  apparatus.  The  recognized 
requirements  are  as  follows:  (i)  A  uniform  and  continuous  supply  of 
fuel  to  the  furnace;  (2)  an  air  supply  slightly  in  excess  of  the  theoreti- 
cal amount  required  for  complete  combustion;  (3)  a  temperature  suffi- 
ciently high  to  ignite  the  gases  that  are  driven  off  from  the  fuel;  (4)  a 
complete  mixture  of  these  gases  with  the  air  supplied  before  they  reach 
a  cooling  surface,  such  as  the  shell  or  tubes  of  a  boiler. 

Factors  Affecting  Value. 

General  Statement. — Some  of  the  factors  that  may  influence  the  com- 
mercial results  obtained  in  a  boiler  are  cost  of  the  coal  as  determined 
by  price  and  heating  value,  care  in  firing,  design  of  the  furnace  and 
boiler  setting,  size  of  grate,  formation  of  excessive  amounts  of  cHnker 
and  ash,  available  draft,  and  size  of  the  coal. 

Moisture. — Coal  as  mined  contains  more  or  less  moisture.  It  is  ex- 
posed to  the  air  in  shipment  and  may  either  dry  out  or  be  drenched  by 
rain.  The  moisture  in  the  coal  deUvered  is  worthless  to  the  purchaser 
and  really  costs  him  a  considerable  amount  in  freight  and  cartage  and  in 
the  loss  of  the  heat  required  for  its  evaporation  in  the  furnace.  If  all 
coal  contained  the  same  proportion  of  moisture,  or  if  the  moisture  in 
coal  delivered  by  a  given  dealer  were  constant  in  amount,  the  purchaser's 
problem,  so  far  as  this  factor  is  concerned,  would  be  simpHfied. 
*  Bulletin  428,  Dept.  Interior,  U.   S.  Geological  Survey. 


i:ngine:e:ring  che:mistry  51 

Under  present  conditions  the  moisture  is  an  important  element  in  the 
valuation  of  a  ton  of  coal.  It  is  evidently  necessary  to  consider  the  coal 
just  as  it  is  received  in  order  to  determine  its  value  to  the  consumer,  but 
chemical  reports  should  be  made  on  both  "dry  coal"  and  "coal  as  received." 
The  report  on  dry  coal  is  convenient  for  comparing  several  coals  to  de- 
termine the  relation  of  each  element  to  the  others;  this  report  is  im- 
portant because  the  moisture  in  the  same  coal  varies  from  day  to  day. 
The  dry  coal  report  is  also  convenient  for  comparing  the  performance 
of  boilers  burning  the  same  or  similar  coals.  Of  several  coals  having  a 
similar  composition,  the  one  that  has  the  least  moisture  and  the  least  ash 
will  generate  the  most  steam  when  burned  under  a  boiler. 

Ash. — Earthy  matter  and  other  impurities  that  will  not  burn  are  classed 
as  ash.  In  commercial  coals  the  proportion  of  ash  may  range  from  4  to 
25  per  cent.  Coals  containing  small  percentages  of  ash  are  the  most 
valuable,  not  only  because  of  their  correspondingly  higher  heating  ca- 
pacity but  because  they  offer  less  resistance  to  the  free  and  uniform  distri- 
bution of  air  through  the  bed  of  coal  in  the  furnace.  The  labor  and  cost 
of  managing  the  fires  and  of  handling  the  ashes  are  also  correspondingly 
less  and  are  items  to  be  considered  in  the  choice  of  a  coal.  With  the 
ordinary  furnace  equipment  there  may  be  a  considerable  loss  of  efficiency 
and  capacity  through  a  large  percentage  of  ash.  With  some  kinds  of 
equipment  it  has  been  found  that  as  the  ash  increases  there  is  a  decided 
drop  in  both  efficiency  and  capacity.  In  some  experiments  made  to  de- 
termine the  influence  of  excessive  amounts  of  ash,  coal  containing  as 
high  as  40  per  cent,  would  generate  no  steam  when  fired  on  a  chain  grate, 
and  therefore  the  efficiency  and  capacity  of  the  plant  would  be  zero.* 
Such  coal  is  not  only  worthless,  but  its  use  involves  a  direct  expense,  due 
to  the  cost  of  handling  it.  Whether  the  result  would  be  similar  with 
equipment  other  than  a  chain  grate  has  not  yet  been  determined.  How- 
ever, coals  so  high  in  ash  that  they  are  unsuited  to  boiler  furnaces  can 
be  utilized  in  gas  producers. 

Volatile  Matter  and  Fixed  Carbon. — The  volatile  part  of  some  coals, 
shown  in  the  analyses,  may  be  all  combustible,  but  it  generally  contains 
some  inert  matter.  The  amount  of  this  differs  in  different  coals,  and 
therefore  it  is  impossible  to  determine  the  heating  value  of  any  coal  from 
its  proximate  analysis  alone.  Moreover,  different  coals  that  contain  the 
same  proportion  of  volatile  matter  do  not  behave  ahke  in  the  furnace. 
In  order  to  determine  the  value  of  one  coal  as  compared  with  another  for 
the  same  purpose  it  is  important  to  know  both  the  chemical  composition 
and  the  British  thermal  units. 

Of  two  coals  of  different  character,  the  one  that  contains  the  higher 
proportion    of    fixed    carbon   is   most    easily    burned,    so    as    to    give    the 

^  Abbott,  W.  ly.,  Some  characteristics  of  coal  as  aflfecting  performance  with  steam 
boilers,  a  paper  read  before  the  Western  Society  of  Engineers,   Chicago,   III. 


52  ENGINEERING   CHEMISTRY 

maximum  efiiciency.  However,  if  the  coal  containing  the  higher  volatile 
matter  is  properly  burned  in  a  suitably  designed  furnace  it  may  be  made 
equally  efficient. 

Sulphur  and  Clinker. — Sulphur  may  be  present  in  the  free  state,  or,  as 
is  more  common,  in  combination  with  iron  or  other  elements.  Other 
impurities  with  sulphur  often  form  a  clinker  that  shuts  out  the  air  and 
increases  the  labor  of  handling  the  furnaces.  It  is  possible,  however,  to 
burn  coals  containing  up  to  5  per  cent,  of  sulphur  without  great  difficulty 
from  clinkers.  A  little  steam  introduced  under  the  grate  will  relieve 
much  of  the  trouble.  Clinker  may  be  due  to  other  causes  than  sulphur, 
as  any  constituents  of  the  ash  which  are  easily  fusible  may  produce  it. 
There  is  need  of  further  investigation  to  determine  the  influence  of  sulphur 
and  the  elements  that  form  ash  in  furnace  fires  during  combustion. 

Size  of  Coal. — The  size  of  the  coal  influences  the  capacity  of  any  given 
equipment,  owing  to  its  effect  on  the  draft.  With  a  poor  draft  fine  coal 
can  not  be  burned  in  sufficient  quantities  to  maintain  the  rated  capacity. 
If  thin  fires  are  resorted  to,  the  efficiency  is  usually  lowered  as  a  result 
of  an  excessive  supply  of  air  through  holes  in  the  fire.  As  a  rule,  when 
dust  and  very  fine  coal  are  fed  into  the  furnace  they  either  check  the 
flow  of  air  or  are  taken  up  by  the  draft  and  after  being  only  partly 
burned  are  deposited  back  of  the  bridge  wall ;  or  they  may  pass  up  the 
stack,  to  the  annoyance  of  people  in  the  vicinity  of  the  plant.  If  this 
dust  is  completely  burned  in  passing  through  the  furnace  there  is  of 
course  no  loss  of  fuel.  Coal  of  uniform  size  forms  the  most  satisfactory 
fuel,  as  it  does  not  pack  so  closely  as  coal  of  different  sizes  mixed. 

In  general  it  may  be  said  that  in  any  market  the  coal  obtainable  at  the 
lowest  price  is  the  most  economical,  provided  the  furnace  equipment  is 
suitable.  If  the  furnace  is  not  so  designed  as  to  permit  the  use  of  the 
cheaper  coal  it  should  be  changed. 

Heat  Units. — The  tests  tend  to  show  that,  other  conditions  being  equal, 
coals  of  similar  composition  are  of  value  in  proportion  to  the  British 
thermal  units,  and  the  determination  of  these  units  in  any  coal  will  give 
approximately  its  value.  It  should  be  remembered,  however,  that  the 
value  of  a  coal  for  any  particular  plant  is  influenced  by  the  character  of 
the  furnace,  for  all  furnaces  are  not  equally  suitable  for  burning  the 
many  grades  of  coal.  Aside  from  this  factor,  coals  may  be  compared  in 
terms  of  the  British  thermal  units  obtained  for  i  cent,  or  on  the  cost  per 
million  heat  units. 

Summary. — In 'the  purchase  of  coal,  then,  attention  should  be  given  to 
the  character  of  the  furnace  equipment  and  the  load,  the  character  of 
coal  best  suited  to  the  plant  conditions,  the  number  of  heat  units  obtain- 
able for  a  unit  price,  the  cost  of  handling  the  coal  and  ash,  and  the 
possibility  of  burning  the  coal  without  smoke  or  other  objectionable 
features. 


ENGINKKRING    CHKMISTRY 


53 


COKE. 


Coke  is  the  residue  left   from  the  destructive  distillation  of 
coal.     Its  composition  is  principally  carbon  and  ash,  but  sulphur 
and  phosphorus  may  be  present  in  small  amounts. 
Composition  of  Cokr. 


Carbon  .  . 
Hydrogen 
Oxygen . . 
Nitrogen . 
Sulphur  . . 

Ash 

Moisture  •  • 


German 
Per  cent. 


84.76 
0.90 
0.34 
1.38 
0-93 
9.42 
2.27 


English 
Per  cent. 


9^-75 

0.45 

1.20 
0.60 

5-50 


French 
Per  cent. 


8435 
0.67 

1-35 

0.40 

1.06 

12.17 


American 
Per  cent. 


81.34 
o  57 
2,40 
0.89 
1.04 

13.76 


Composition  or  Pocohontas  Coke. 

Per  cent. 

Moisture    0.70 

Volatile  matter    1.25 

Fixed  carbon    91.16 

Ash    7.59 

Sulphur    0.632 

Phosphorus 0.005 

Compression  strength  236  pounds  per  square  inch. 
I  ton  occupies  about  85  cubic  feet. 

Comparative  Coke  Analysis. 


Bee  hive 

Retort 

Vertical 

ovens 

coke  ovens 

retort 

0.35 

1.25 

1-35 

0.34 

1. 61 

1-73 

92.69 

86.66 

87.40 

5.89 

10.48 

952 

0.74 

0.77 

0.99 

1.83 

1.90 

1.82 

52.07 

49-49 

59-25 

47.93 

50.51 

40.75 

Horizontal 
retort 


Moisture 

Volatile  compounds 

Fixed  carbon 

Ash   

Sulphur 

Real  gravity 

Per  cent,  coke 

Per  cent,  cells 


2.57 

3-84 

86.05 

7-54 
0.96 

1.73 
53.89 
46.11 


REPORT  OF  THE  COMMITTEE  ON  STANDARD  METHODS  FOR 
DETERMINING  THE  CONSTITUENTS  OF  FOUNDRY  COKE. 

(American  Foundry  Association.) 


Sampling. 

Each  carload  of  coke  shall  be  considered  as  a  unit.    While  the 
car  is  being  unloaded,  full  length  pieces  of  coke  shall  be  taken 


54  ENGINKERING    CHEMISTRY 

at  about  equal  intervals  and  a  sample  approximately  the  size  of 
an  egg  taken  from  each  end  and  also  from  the  middle  of  each 
piece,  until  25  to  40  pounds  are  obtained.  Should  it  be  necessary 
to  sample  from  a  stock  pile,  25  to  30  pounds  of  sample  obtained 
as  above  directed,  shall  be  taken  for  each  50  tons  in  the  pile, 
care  being  used  to  get  the  piece  from  different  places  which  will 
give  a  fair  average  sample. 

Preparing  the  Sample. 

Crush  the  sample  between  hardened  surfaces,  preferably  of 
manganese  or  chrome  steel,  until  all  the  material  passes  through 
a  ^-inch  mesh  sieve.  Quarter  this;  reserve  one  portion  for 
moisture  determination  and  crush  the  other  portion  until  it  will 
all  pass  through  a  ^-inch  mesh  sieve,  and  again  quarter  down 
until  about  2  pounds  remain.  Crush  this  until  it  will  pass  a 
No.  20-mesh  sieve,  and  quarter  down  to  about  20  grams.  Grind 
this  until  it  all  passes  through  a  No.  lOO-mesh  sieve. 

Moisture. 

Dry  I  kilogram  of  y^-'mch  mesh  sample  to  constant  weight  at 
104°  to  107°  C.  The  loss  in  weight  shall  be  calculated  to  per 
cent,  moisture.  Moisture  shall  be  determined  on  the  ground 
sample  by  getting  the  loss  in  weight  when  I  gram  sample  is 
heated  in  an  open  platinum  crucible  of  about  20  cc.  capacity  for 
I  hour  at  104°  to  107°  C.  The  moisture  on  the  ground  sample 
shall  be  used  to  calculate  the  other  results  gotten  from  the 
ground  sample  to  percentages  in  the  coarse  undried  sample. 

Volatile  Matter. 

Cover  the  crucible  containing  the  dried  sample,  with  another 
crucible  (either  platinum  or  porcelain)  of  such  a  size  that  it  will 
fit  closely  to  the  sides  of  the  outer  crucible,  and  its  bottom  will 
rest  Ys  inch  to  ^  inch  above  the  bottom  of  the  outer  crucible. 

Ignite  3^  minutes  with  the  Bunsen  burner  and  3^  minutes 
with  the  blast  lamp.  I^et  cool,  remove  the  inner  crucible  and 
reweigh  the  outer  crucible  with  contents.  The  loss  of  weight  is 
volatile  matter. 

Ash  and  Fixed  Carbon. 

Ignite  the  sample  upon  which  the  volatile  matter  was  deter- 


e:ngine;kring  chemistry  55 

mined  until  all  the  carbon  is  burned,  having  the  crucible  open 
and  inclined.  The  ash  should  be  tested  for  unburned  carbon  by 
moistening  it  with  alcohol,  which  will  show  black  any  carbon 
remaining.  After  all  carbon  is  burned,  the  weight  of  the  cru- 
cible and  ash  minus  the  weight  of  the  crucible,  gives  the  amount 
of  ash  in  the  sample. 


Fig.  4a. 

The  amount  of  fixed  carbon  is  obtained  by  subtracting  the 
weight  of  the  crucible  and  ash  from  the  weight  of  the  crucible 
and  residue  from  the  volatile  matter  determinations. 

Sulphur. 

Crucible. — A  soft  steel  or  nickel  crucible  of  about  40  cc. 
capacity,  the  lid  being  perforated  with  a  small  hole  for  the  in- 
troduction of  the  igniting  wire. 

Crucible  Stand. — Any  arrangement  suitable  for  holding  the 
crucible  firmly  in  place  and  out  of  contact  with  the  beaker  during 
the  peroxide  combustion. 

Determination. — To  the  dry  crucible  add  first  12  grams  of 
sodium  peroxide  and  0.5  gram  of  powderd  potassium  chlorate, 
then  exactly  0.7  gram  of  coke  (80-mesh)  and  mix  thoroughly  by 
means  of  a  small  spatula.  Place  the  covered  crucible  on  its  stand 
in  a  20-ounce  beaker  containing  enough  water  to  immerse  the 
lower  half  of  the  crucible. 

Ignite  the  crucible  contents  by  thrusting  in,  for  a  moment,  a 
red  hot  wire  through  the  lid  hole.  Wait  2  minutes  or  longer  for 
the  mass  to  cool  somewhat,  remove  the  stand  and  tip  over  the 
crucible  on  its  side  in  the  water.  After  the  fusion  dissolves, 
rinse  and  remove  the  crucible. 


56  ENGINEERING    CHEMISTRY 

Acidify  the  solution  with  hydrochloric  acid,  then  add  ammonia 
in  slight  excess,  filter  and  wash.  To  the  filtrate  add  a  drop  of 
methyl  orange,  then  hydrochloric  acid  from  a  graduated  pipette 
or  burette  until  0.5  cc.  in  excess.  Bring  to  boiling,  add  drop 
wise  about  10  cc.  of  barium  chloride  solution,  continue  boiling 
at  least  15  minutes  longer,  and  allow  it  to  stand  in  a  warm  place 
for  not  less  than  2  hours,  filter,  wash  until  the  silver  nitrate  test 
shows  no  chlorides,  ignite  and  weigh  as  BaS04. 

Grams  BaSO^  X  i9-6  =  per  cent,  sulphur. 
Phosphorus. 

Ignite  5  grams  of  coke  in  a  platinum  dish  or  large  platinum 
crucible  until  all  the  carbon  is  burned  off,  then  add  10  cc.  hydro- 
chloric acid  (i-i)  and  20  cc.  hydrofluoric  acid  and  evaporate  to 
dryness  and  ignite  at  a  dull  red  heat.  Fuse  the  residue  with 
about  iy2  grams  of  sodium  carbonate  and  2  grams  of  potassium 
nitrate.  Cool,  place  the  dish  in  a  beaker  of  water  and  boil. 
Clean  and  remove  the  dish.  iVcidify  the  solution  with  hydro- 
chloric acid,  precipitate  with  ammonia,  boil,  filter  and  wash  with 
hot  water.  Wash  the  filter  w^ith  warm  dilute  nitric  acid  to  dis- 
solve the  precipitate.  Should  it  not  dissolve,  wash  with  warm 
dilute  hydrochloric  acid  until  dissolved.  In  the  latter  case,  it  will 
be  necessary  to  evaporate  to  about  5  cc,  add  30  cc.  nitric  acid 
(1.20  specific  gravity)  ;  again  evaporate  to  about  5  cc.  and  add 
30  cc.  nitric  acid  (1.20  specific  gravity).  After  heating  the  solu- 
tion to  between  70°  and  90°  C,  add  50  cc.  of  molybdate  solu- 
tion. Agitate  the  solution  a  few  minutes,  then  filter,  and  wash  five 
times  with  a  3  per  cent,  nitric  acid  solution,  and  five  times  with  a 
0.1  per  cent,  potassium  nitrate  solution.  Transfer  the  precipitate 
and  filter  to  the  flask  in  which  the  precipitate  was  made.  Add 
30  cc.  water,  then  NaOH  (N/5)  from  a  burette  until  in  excess, 
keeping  the  solution  agitated.  When  the  yellow  precipitate  is 
all  dissolved  add  o.i  cc.  of  phenolphthalein  solution  as  indicator, 
and  then  titrate  with  HoSO^CN^). 

cc.   (N/5)   NaOH  ^  cc.   (N/5)   H,SO,  X  0.0054  = 
per  cent,  phosphorus. 

To   make  the   molybdate   solution,   add    100  grams   molybdic 


KNGTNKERING    CHEMISTRY  57 

acid  to  250  cc.  water,  and  to  this  add  150  cc.  ammonia.  Stir  until 
all  is  dissolved  and  add  65  cc.  nitric  acid  (1.42  specific  gravity). 
Make  another  solution  by  adding  400  cc.  concentrated  nitric  acid 
to  1,100  cc.  water,  and  when  the  solutions  are  cool,  pour  the 
first  slowly  into  the  second  with  constant  stirring  and  add  a 
couple  of  drops  of  ammonium  phosphate. 

Dr.  Andrew  A.  Bl<air,  Prof.  Thos.  B.  Stili^man, 

Herbert  E.  Fiei.d,  Warren  J.  Keeler, 

J.  O.  Handy,  H.  C.  Loudenbeck, 

A.  P.  Ford,  Henry  Souther, 

Froeheing  &  Robertson,      R.  S.  MacPherran, 

J.  R.  Harris,  H.  E.  DieeER,  Secretary, 

Dr.  L.  C.  Jones,  Committee. 


THE  PHYSICAL  TESTING  OF  COKE. 


Determination  of  the  True  Specific  Gravity  of  Coal 
and  Coke  Substance.* 

Ordinary  Method. 
To  determine  the  true  specific  gravity  of  coal  and  coke  sub- 
stance, the  procedure  is  as  follows :  Approximately  3.5  grams 
of  the  60-mesh  coal  or  coke  is  weighed  and  introduced  into  a  50 
cc.  pycnometer  with  about  30  cc.  of  distilled  water.  In  order  to 
avoid  loss  of  particles  of  the  sample  during  boiling,  a  one  bulb 
6-inch  drying  tube  is  connected  with  the  pycnometer  by  means  of 
a  small  piece  of  pure  gum  tubing.  The  other  end  of  the  drying 
tube  is  connected  with  the  aspirator.  Suction  is  applied  and  the 
contents  of  the  flask  are  gently  boiled  on  the  water  bath  under 
partial  vacuum  for  3  hours  in  order  to  expel  all  air  from  the 
sample.  The  pycnometer  is  then  detached,  almost  filled  with 
boiled  and  cooled  water,  allowed  to  cool  to  the  temperature  of 
the  balance  room,  stoppered,  and  weighed.  The  temperature  of 
the  contents  of  the  pycnometer  is  taken  immediately  after  weigh- 
ing. Each  pycnometer  is  accurately  calibrated  and  a  table  is 
constructed  giving  its  capacity  in  grams  of  water  at  different 
temperatures. 

*  Technical    Paper    No.    8,    Bureau    of    Mines,    Methods    of    Analyzing    Coal    and 
Coke,    1913. 


58  Engine:i:ring  che:mistry 

The  true  specific  gravity  is  determined  by  use  of  the  following 
formula : 

W 
True  specific  gravity 


W  —  (W  —  P) 

in  which  W  =  weight  in  grams  of  dry  coke  =  weight  in  grams 
of  sample  —  its  moisture  content. 
W   =   weight   in   grams   of   pycnometer   -\-   dry   coke 

-|-  water  to  fill. 
P  =  weight  in  grams  of  pycnometer  -|-  water  to  fill. 

Sp^ciat,  Method. 

The  Hogarth  flask  recommended  by  Blair^  for  the  determina- 
tion of  the  specific  gravity  of  iron  ores  is  more  convenient  and 
accurate  for  routine  determinations  of  the  specific  gravity  of 
coal  or  coke  substances  than  is  the  ordinary  pycnometer  described 
in  the  preceding  method.  With  the  ordinary  pycnometer  it  is 
difficult  to  insert  the  stopper  without  catching  some  floating  par- 
ticles between  the  stopper  and  neck. 

With  the  Hogarth  flask  there  is  no  such  difficulty.  The 
method  of  determination  with  the  Hogarth  flask  is  as  follows : 

A  lo-gram  portion  of  the  6o-mesh  coal  or  coke  is  weighed 
and  is  carefully  introduced  into  the  weighed  flask  with  distilled 
water  enough  to  fill  the  flask  half  full.  The  capacity  of  the 
Hogarth  flasks  as  obtained  on  the  market  varies  from  lOO  to  125 
cc.  The  flask  is  then  placed  on  a  small  electric  hot  plate,  in  a 
lO-inch  vacuum  desiccator.  The  desiccator  is  evacuated  by 
means  of  an  aspirator  or  air  pump.  A  current  sufficient  to  keep 
the  water  boiling  is  passed  through  the  hot  plate.  With  an  ef- 
ficient vacuum  pump  all  the  air  is  expelled  in  30  minutes.  -The 
flask  is  then  removed  from  the  desiccator,  filled  to  the  tubulure 
with  recently  boiled  and  cooled  distilled  water,  and  the  stopper 
inserted.  It  is  advisable  to  apply  a  thin  film  of  vaseline  to  the 
stopper  to  prevent  leakage. 

After  the  flask  has  been  cooled  to  about  25°  C.  in  a  water 
thermostat,  distilled  water  that  has  been  cooled  in  the  same 
thermostat  is  drawn  through  the  tubulure  until  the  water  level  is 
slightly  above  the  mark  on  the  capillary  of  the  stopper.     This 

^  Blair,  A.  A.,  The  Chemical  Analysis  of  Iron,  7th  ed.,   1908,  p.  278. 


kngine:ering  che:mistry  59 

may  be  done  without  removing  the  flask  from  the  thermostat  by- 
inserting  the  end  of  the  tubulure  in  a  small  beaker  of  water  and 
applying  a  slight  suction  on  the  stopper.  The  flask  should  re- 
main in  the  thermostat  until  the  temperature  of  contents  is  ex- 
actly 25°  C.  The  water  level  is  adjusted  to  the  mark  on  the 
capillary  by  touching  a  piece  of  filter  paper  to  the  end  of  the 
tubulure  or  by  drawing  in  a  little  water.  The  flask  is  then  re- 
moved from  the  thermostat,  wiped  dry,  and  weighed.  The  true 
specific  gravity  is  calculated  as  in  the  preceding  method. 
The  value  for  P  is  obtained  by  filling  the  flask  with  boiled 
water,  cooling,  and  weighing,  as  described  above. 

By  this  method  no  difficulty  is  experienced  in  duplicating  the 
figures  for  specific  gravity  to  two  decimal  places. 

Determination  of  the  Apparent  Specific  Gravity. 

The  apparatus  used  for  determination  of  the  apparent  specific 
gravity  consists  of  a  galvanized  iron  cylinder,  which  is  filled  with 
water  to  the  water  line.  In  the  cylinder  is  immersed  a  hydrom- 
eter made  of  brass.  On  the  top  of  the  hydrometer  are  2  pans. 
The  upper  one  is  used  for  weights  and  the  lower  for  the 
sample.  Below  the  air  buoy  is  a  brass  cage  perforated  with  many 
holes  to  allow  the  air  to  escape  when  the  instrument  is  immersed. 
The  cage  carries  the  sample  when  it  is  weighed  under  water. 

The  method  of  determining  the  apparent  specific  gravity  is  as 
follows :  Brass  weights  are  placed  on  the  upper  pan  until  the 
hydrometer  sinks  to  a  mark  on  the  stem  between  the  copper  pan 
and  the  buoy.  The  total  weight  required  is  recorded.  The 
weights  are  removed,  and  about  500  grams  of  the  sample  in  lump 
form  (about  i^  to  2-inch  cubes)  is  placed  in  the  copper  dish. 
Brass  weights  are  then  added  until  the  hydrometer  sinks  to  the 
mark  on  the  stem.  The  difference  in  the  weights  used  gives  the 
weight  of  the  sample  in  air.  The  sample  is  then  carefully  trans- 
ferred to  the  brass  cage  below  the  buoy.  The  weights  on  the 
upper  pan  are  now  adjusted  until  the  instrument  again  sinks  to 
the  mark  on  the  stem.  The  weight  required  to  sink  the  hydrom- 
eter to  the  mark  with  no  sample  on  the  upper  pan  nor  in  the 
brass  cage  minus  the  weight  required  to  sink  it  to  the  mark  with 


6o 


ENGINEERING   CHEMISTRY 


the  sample  immersed  in  the  cage  equals  the  weight  of  the  coke 
in  water.    Then, 

If  the  weight  of  the  sample  in  air  =  x  and  the  weight  of  the 
sample  in  water  =  y, 

X 


And  IOC  X 


the  apparent  specific  gravity 
apparent  specific  gravity 


x—y 
percentage  by  volume 


true  specific  gravity 
of  coke  substance. 

Also,  lOO  —  percentage  by  volume  of  coke  substance  =  per- 
centage by  volume  of  cell  space. 

In  making  apparent  specific  gravity  determinations  of  coke  the 
sample  should  preferably  be  in  lumps  of  nearly  the  same  size  and 
shape.  When  the  sample  is  immersed,  the  hydrometer  should  be 
moved  rapidly  up  and  down  in  the  water  a  number  of  times  in 
order  to  remove  air  bubbles.  Since  coke  samples  are  porous,  they 
take  up  water  rapidly  and  should  not  be  allowed  to  remain  in 
contact  with  water  more  than  5  minutes  during  a  determination. 
By  observing  the  above  mentioned  precautions  satisfactory  re- 
sults can  be  obtained.  All  samples  should  be  thoroughly  dried 
before  specific  gravity  determinations  are  made. 

A  series  of  nine  specimens  from  the  Bradford  Works  of  Frick 
&  Co.,  yielded  as  follows : 


Maximum 
Minimum  . 
Average   . . 


Moisture 


0.096 
0.008 
0.034 


True 
sp.  gr. 


1.79 

1.73 
1.76 


Apparent 
sp.  gr. 


1-033 
0.819 
0.802 


Per  cent. 

of  cells  by 

vol. 


54  37 
42.20 

49-37 


Cc.  in  100 
grams. 


66.31 
40.83 
55-73 


Twelve  samples  of  coke  from  El  Moro,  Colorado,  gave  the 
following : 


Maximum 
Minimum 
Average    . 


Moisture 


0.225 
0.025 
0.125 


True 
sp.  gr. 


1.85 
1. 61 

1-73 


Apparent 
sp.  gr. 


1.047 
0.766 
0.906 


Per  cent. 

of  cells  by 

vol. 


54.66 
61.47 
58.06 


Cc.  in  100 
grams. 


71.36 
41.56 
56.46 


i:nginke:ring  chdmistry  6l 

Compression  Test. 

There  is  no  standard  method  of  making  this  test  in  this 
country.  In  Germany  the  Thorner  compression  machine  is  used. 
Good  coke  gives  with  this  machine  a  compression  strength  of  i6o 
to  1/5  kilos  per  cc. 

The  Riehle  universal  compression  machine,  i,cx)0  pounds 
capacity,  is  sometimes  used  in  this  country  for  this  test,  vis. : 
The  specimen  of  coke  is  prepared  as  i-inch  cube.  The  speci- 
men is  placed  on  the  plunger  which  rests  on  the  beam ;  the  upper 
plunger  screw  is  adjusted  to  come  in  contact  with  the  specimen. 
Load  is  then  applied  by  moving  poise  out  on  beam  until  the 
specimen  breaks  up.  The  load  required  to  do  this  is  read  in 
pounds  on  the  beam. 

F.  W.  Sperr,  Jr.,  chief  chemist,  Plant  No.  2,  Inland  Steel  Co., 
writes  relative  to  the  compression  test  as  follows : 

The  physical  tests  that  are  usually  made  in  connection  with  coke  oven 
and  blast  furnace  operation  and  foundry  practice  are  simply  the  so-called 
"shatter  test"  and  the  well-known  determinations  of  apparent  and  true 
specific  gravity  and  porosity.  In  addition,  some  plants  have  made  a 
practice  of  testing  their  coke  for  its  resistance  to  abrasion  by  means  of 
an  apparatus  similar  to  the  rattler  which  is- commonly  used  for  testing 
paving  brick.  Studies  of  the  cell  structure  of  coke  by  examination  of 
surfaces  of  fracture  are  also  considered  very  important,  but  have  so  far 
not  been  satisfactorily  standardized. 

With  reference  to  crushing  tests  which  you  mention  particularly,  I 
can  state  without  qualification  that  each  and  all  of  the  many  attempts 
that  I  know  have  been  made  to  test  coke  in  this  way  have  resulted  in 
failure.  Please  refer  to  Bulletin  No  336  of  the  U.  S.  Geological  Survey, 
"Washing  and  Coking  Tests  of  Coal,"  etc.,  which  not  only  reports  the 
unsatisfactory  experience  of  the  Geological  Survey  investigators  with  this 
test,  but  brings  out  the  fact  that,  after  all,  the  test  is  of  very  little  prac- 
tical importance.  Calculation  will  show  that  even  in  a  large  blast  furnace 
the  coke  does  not  have  to  withstand  a  pressure  of  more  than  about  50 
pounds  per  square  inch  and  a  very  poor  coke  will  have  sufficient  com- 
pression strength  to  carry  all  the  burden  required.  The  most  important 
reasons  for  failure  of  the  crushing  test  as  applied  to  coke  are  the  lack 
of  uniformity  of  the  material  and  the  difficulty  of  preparing  satisfactory 
test  pieces. 

The  Semet  Solvay  Company  has  used  the  rattling  test  more  than  any 
other  of  which  I  am  aware ;  but  they  apply  it  more  to  special  investiga- 
tions than  to  tests  of  regular  production.     Most  of  the  apparatus  that  I 


62  ENGINEERING    CHEMISTRY 

have  seen  is  of  "home  made"  type.  One  is  simply  a  50-gallon  oil  barrel 
rotated  by  a  belt  from  a  counter  shaft  for  a  certain  number  of  turns.  A 
coke  may  give  quite  different  results  in  the  rattler  from  what  it  shows  in 
the  shatter  test. 

Some  work  has  been  done  towards  standardizing  the  study  of  cell 
structure  by  photographing  surfaces  of  fracture  both  with  and  without 
magnification,  and  it  would  be  well  if  some  investigator  would  take  this 
subject  up  and  develop  it  more  thoroughly. 

SUGGESTED  SPECIFICATIONS  FOR  FOUNDRY  COKE.* 

Coke  bought  under  these  specifications  should  be  massive,  in 
large  pieces,  and  as  free  as  possible  from  black  ends  and  cinder. 

Sampling. — Each  car  load,  or  its  equivalent,  shall  be  con- 
sidered as  a  unit,  and  sampled  by  taking  from  the  exposed  sur- 
face at  least  one  piece  for  each  ton,  and  so  as  to  fairly  repre- 
sent the  shipment.  These  samples,  properly  broken  down  and 
ground  to  the  fineness  of  coarse  sawdust,  well  mixed  and  dried 
before  analysis,  shall  be  used  as  a  basis  for  the  payment  of  the 
shipment.  In  case  of  disagreement  between  buyer  and  seller,  an 
independent  chemist,  mutually  agreed  upon  shall  be  employed  to 
sample  and  analyze  the  coke,  the  cost  to  be  borne  by  the  party  at 
fault. 

Base  Analysis. — The  following  analysis,  representing  an  aver- 
age grade  of  foundry  coke,  capable  of  being  made  in  any  of 
the  districts  supplying  foundries,  shall  be  considered  the  Base, 
premiums  and  penalties  to  be  calculated  thereon  as  determined 
by  the  analysis  on  an  agreed  base  price : 

Volatile  matter   i.oo 

Fixed  carbon    85.50 

Ash  '. 12.00 

Sulphur    1. 10 

Moisture. — Payment  shall  be  made  on  shipments  on  the  basis 
of  "dry  coke."  The  weight  received  shall  therefore  be  corrected 
by  deducting  the  water  contained.  (Note: — Coke  producers 
should  add  sufficient  coke  to  their  tonnage  shipments  to  make 
up  for  the  water  included,  as  shown  by  their  own  determina- 
tions.) 

*  Communicated  to  the  writer  by  Dr.   Richard  Moldenke,   from   the   Transactions 
Amer.  Foundry  Association,   19 10. 


i:NGINEi:RING    CHEMISTRY  63 

Volatile  Matter. — For  every  0.50,  or  fraction  thereof,  above 
the  1. 00  allowed  deduct  .  .  .  cents  from  the  price.  Over 
2.50  rejects  the  shipment,  at  the  option  of  the  purchaser. 

Fixed  Carbon. — For  every  i.oo  or  fraction  thereof,  above 
85.50  add,  and  for  every  i.oo  or  fraction  thereof  below  85.50 
deduct  .  .  cents.  Below  78.50  rejects  the  shipment  at  the  option 
of  the  purchaser. 

Ash. — For  every  0.50  or  fraction  thereof  below  12.00,  add, 
and  for  every  0.50  or  fraction  thereof  above  12.00,  deduct  .  . 
cents  from  the  price.  Above  15.00  rejects  the  shipment  at  the 
option  of  the  purchaser. 

Sulphur. — For  every  o.io  or  fraction  thereof  below  i.io  add, 
and  for  every  o.io  or  fraction  thereof  above,  deduct  .  .  cents 
from  the  price.  Above  1.30  rejects  the  shipment  at  the  option 
of  the  purchaser. 

Shatter  Test. — On  arrival  of  the  shipment,  the  coke  shall  be 
subjected  to  a  shatter  test,  as  described  below.  The  percentage 
of  fine  coke  thus  determined,  above  5  per  cent,  of  the  coke,  shall 
be  deducted  from  the  amount  of  coke  to  be  paid  for  (after  al- 
lowing for  the  water),  and  paid  at  fine  coke  prices,  previously 
agreed  upon.  Above  15  per  cent,  fine  coke  rejects  the  ship- 
ment at  the  option  of  the  purchaser.  Fine  coke  shall  be  coke 
that  passes  through  a  wire  screen  with  square  holes  2  inches  in 
the  clear. 

The  apparatus  Fig.  4b,  for  making  the  shatter  test  should  be  a 
box  capable  of  holding  at  least  100  pounds  of  coke,  supported  with 
the  bottom  6  feet  above  a  cast  iron  plate.  The  doors  on  the  bottom 
of  the  box  shall  be  so  hinged  and  latched  that  they  will  swing 
freely  away  when  opened,  and  will  not  impede  the  fall  of  the 
coke.  Boards  shall  be  put  around  the  cast  iron  plate  so  that  no 
coke  may  be  lost. 

A  sample  of  approximately  50  pounds  is  taken  at  random 
from  the  car,  using  a  i^-inch  tine  fork,  and  placed  in  the  box 
without  attempt  to  arrange  it  therein.  The  entire  material 
shall  be  dropped  four  times  upon  the  cast  iron  plate,  the  small 
material  and  the  dust  being  returned  with  the  large  coke  each  time. 

After  the  fourth  drop  the  material  is  screened  as  above  given. 


64 


ENGINEERING    CHEMISTRY 


the  screen  to  be  in  horizontal  position,  shaken  once  only,  and 
no  attempt  made  to  put  the  small  pieces  through  specially. 


Fig.   4b. — Lokc   shattcr-tcst   apparatus. 

The  coke  remaining  shall  be  weighed  and  the  percentage  of 
the  breeze  determined. 

If  the  sum  of  the  weight  indicates  a  loss  of  over  i  per  cent., 
the  test  shall  be  rejected  and  a  new  one  made. 

Rejection  by  reason  of  failure  to  pass  the  shatter  test  shall  not 
take  place  until  at  least  two  check  tests  have  been  made. 

The  following  is  a  report  upon  a  sample  of  Connellsville  coke : 
ANAI.VSIS  OF  THK  Coal  from  which  the  Coke  was  Made. 

Per  cent. 

Water 1405 

Volatile  and  combustible  matter 29.885 

Fixed  carbon 57. 754 

Sulphur 1. 113 

Ash 9.895 


Total 100.05  2 


Kngini:kring  che:mistry 


65 


Analysis  of  the  Coke.  Per  Cent. 

Water    0.030 

Volatile  and  combustible  matter 0.460 

Fixed  carbon    89.576 

Sulphur     0.821 

Ash    9.113 


Total    100.00 

Specific  Gravity,  Porosity,  Per  cent,  of  Cei.i.s,  Weight  per  Cubic 
Foot,  etc.,  of  the  Coke. 

Apparent   specific   gravity    0.892 

True    specific    gravity 1.760 

Per  cent,  of  cells  by  volume ,  49.37 

Volume  of  cells ;  cc.  in  100  grams 55-73 

>>^ 

"^  . 


John  Fulton,  M.  E.,  gives  the  following  as  the  standard  for 
the  chemical  and  physical  properties  of  coke : 


Coke. 

Method  of  Manufacture 

To  be  Used  For 

Style                            Charge 

of                                    in 
oven          Size           pounds 

Yield       Time 
in  per         of 
cent,      cooking 

Kind                Size  of 

of                      fur- 
furnace                nace 

11^X5^6^' 

48 

Bee-hive                     7600 

63       and 

Iron  blast.  70^  X  16^ 

12^  X  6^ 

72 

c 
0 

^ 

0 

R 

a; 

III 
11:^ 

tfl   CJ    CI 

m 

0 
0 

CO 

Chemical  analysis 

0 

IT.    0 

1" 

§1 

0 

g 
'S 

•55 
0 

1 

u 

-a 

5 

0 

s 

Dry 

Wet 

Dry 

Wet 

Coke 

Cells 

15-47 

23.67 

58.98 

87.34 

49.96 

50.04 

301 

120 

I 

2.5 

1.89 

87.46 

0.49 

11.32 

0.69 

0.029 

o.on 

LIMESTONE. 


The  composition  of  the  various  limestones  and  the  methods  of 
analysis  of  the  same  are  of  importance  to  the   Chemical   En- 
gineer.    The  following  scheme  of  analysis  is  arranged  as  a  sim- 
plified method. 
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i:ngine:e:ring  che:mistry 


67 


68  e:ngine:e:ring  chemistry 

Determination  of  Carbon  Dioxide  in  Limestone. 

The  U-tube  B  (Fig.  5)  contains  water  acidified  with  sulphuric 
acid.  No  more  of  the  mixture  should  be  placed  in  the  tube  than 
just  sufficient  to  make  a  seal  at  the  base  of  the  U-tube. 

The  U-tubes  C  and  D  contain  granulated  calcium  chloride.  As 
this  chemical  often  contains  CaO  it  is  always  advisable  before 
connecting  these  tubes  with  the  apparatus  to  first  pass  carbon 
dioxide  gas  through  them  to  saturate  any  CaO,  and  then  aspirate 
with  air,  to  exhaust  all  free  carbon  dioxide. 

The  U-tubes  E  and  F  contain  soda-lime  granulated,  medium 
size,  and  are  weighed  carefully  before  using  the  apparatus. 

The  U-tube  G  contains  calcium  chloride  to  absorb  any  moist- 
ure that  might  enter  from  the  water  in  the  aspirator. 

Two  grams  of  the  limestone  are  transferred  to  the  flask  A,  and 
the  flask  connected  with  the  apparatus  shown  in  Fig.  5. 

Dilute  hydrochloric  acid  (50  cc.)  is  allowed  to  run  into  the 
flask  A  from  the  funnel  tube,  and  heat  is  gradually  applied  until 
the  liquid  in  the  flask  begins  to  boil. 

Connect  the  Bennert^  drying  apparatus  with  the  funnel  tube 
of  flask  A,  the  aspirator  with  G,^  and  slowly  aspirate  air  through 
the  entire  apparatus.  The  carbon  dioxide  is  all  absorbed  by  the 
soda-lime.  During  the  absorption  of  the  carbon  dioxide  by  the 
soda-lime,  the  tube  E  becomes  heated.  It  must  be  cooled  to  the 
surrounding  temperature  before  weighing. 

After  aspirating  about  4  liters  of  air,  weigh  the  soda  lime 
tubes.  Replace  the  tubes  E  and  F  with  the  apparatus  and  as- 
pirate about  2  liters  of  air  and  again  weigh.  This  must  be  re- 
peated until  the  weight  of  the  tubes  remains  constant. 

Grams. 

Soda-lime  tubes  and  CO2 48.2270 

Soda-lime  tubes  47.4307 

CO2    0.7963 

°-^^'^^X'°°  =  39-81  per  cent.     CO,. 

1  The  first  cylinder  contains  a  strong  solution  of  potassium  hydrate,  the  second  cylin- 
der H2SO4  concentrated,  and  the  large  U-tube  granulated  calcium  chloride  (anhydrous). 
2  Any  other  means  of  exhaust  can  be  used  that  can  be  regulated. 


e:ngini:e:ring  che:mistry 


69 


The  carbon  dioxide  may  also  be  determined  as  follows : 
Weigh  I  gram  of  the  powdered  limestone  and  transfer  it  to 
the  carbon  dioxide  apparatus  (Fig.  6)  through  the  opening  in  C. 


Fill  the  tube  A  half  full  with  strong  sulphuric  acid.  Fill  the 
tube  B  with  hydrochloric  acid,  dilute  (1:1),  then  weigh  the  ap- 
paratus and  contents.  Remove  the  upper  stopper  in  B  and  care- 
fully allow  the  hydrochloric  acid  to  run  into  the  flask  and  dis- 
solve the  limestone;  close  the  stop-cock  as  soon  as  the  hydro- 
chloric acid  has  entered  the  flask;  carbon  dioxide  will  be  evolved 
and  pass  out  through  the-tube  A,  in  which  tube  the  sulphuric  acid 
acts  as  a  drier  on  the  evolved  carbon  dioxide.  Upon  solution  of 
the  limestone,  air  is  slowly  aspirated  through  B,  C,  and  A,  by 
connecting  the  copper  outlet  of  A  with  an  aspirator.  When  the 
carbon  dioxide  is  all  displaced  by  air  in  A,  B  and  C,  the  apparatus 
and  contents  are  allowed  to  cool,  then  weighed.  The  difference 
between  this  weight  and  the  first  weight  represents  the  amount  of 
carbon  dioxide  evolved  from  the  i  gram  of  limestone. 
Thus,  I -gram  limestone  taken  : 

Grams. 
Weight  of  apparatus  after  evolving  CO2 17.267 

Weight  of  apparatus  before  evolving 16.871 


CO.  0.396 

0.3960    X    100  r  .         r^r^ 

-^2. — d 31^  39.6  per  cent.  COj. 

This  apparatus  is  easily  and  rapidly  operated  giving  results 
agreeing  within  i  per  cent,  and  in  many  commercial  analyses  the 
carbon  dioxide  can  be  determined  with  it  instead  of  using  the 
more  complex  apparatus  for  accurate  work  shown  in  Fig.  5. 


70  engine:e:ring  che:mistry 

Limestone. 

Resume.  Pe^  cent. 

Organic  matter    2.02 

Silica    4.80 

Iron  and  aluminum  oxides 1,40 

Lime    42.16 

Magnesia    7.31 

Sulphur  trioxide   2.50 

Carbon  dioxide    39.81 


100.00 
The  SO3  is  united  with  CaO  to  form  CaSO*. 
SO3  :  CaSO*  : :  2.50  :  x 
X  =  4.25 
Subtracting  the   1.75  CaO  used  to  unite  with  the   SO3  there  remains 
40.41  CaO  to  unite  with  CO2. 

CaO  :  CaCOa  : :  40.41  :  x 

X  =  72.17 

MgO  :  MgCOa  : :  7.31  :  ^' 

■v  =  15-36 

Per  cent. 

Organic  matter  2.02 

Silica,  etc 4.80 

Iron  and  aluminum  oxides 1,40 

Calcium  sulphate 4.25 

Calcium  carbonate  72.17 

Magnesium  carbonate   15.36 


100.00 
The  analyses  shows  the  limestone  to  be  a  dolomite  or  magne 
sian  limestone.    The  following  is  an  analysis  of  high-grade  lime- 
stone : 

Per  cent. 

Silica 0.87 

Iron  and  aluminum  oxides 0.12 

Calcium  carbonate 98.60 

Magnesium  carbonate    0.22 


99.81 
It  is  seldom  that  phosphoric  acid  is  determined  in  limestone, 
since  it  usually  amount  to  less  than  0.02  per  cent.    It  is  essential 
however,  in  cases  where  the  limestone  is  to  be  used  in  blast-fur- 
naces making  Bessemer  pig  iron. 


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01 


72  ENGINKERING   CHEMISTRY 

EXAMPI^E. 

Ten  grams  of  iron  ore  taken. 

Grams. 

Insoluble  residue  and  crucible 10.551 

Crucible    10.301 

0.250 

0.25  X  100  .       ,  , 
=  2.50  per  cent,  insoluble  matter. 

Solution  =  500  cc. 
Phosphorus  pentoxide  ( 100  cc. ) .     See  appendix. 

Iron. 

Fifty  cc.  reduced  with  zinc  or  SnCl2  requires  34.65  cc.  stand- 
ard K.Cr^O-  solution.  One  cc.  K^CrgO^  corresponds  to  0.0168 
gram  iron,  34.65  X  0.0168  =  0.58212  gram  iron  in  50  cc.  of  the 
iron  solution. 

„,        0.58212  X  10  X  100         o  ^    .     , 

Then  ^^ ^ ^ =58.21  per  cent.  Fe  in  the  ore. 

10  ^  r 

=  83.16         "         FegOa  in  the  ore. 

Sulphur  trioxide  (50  cc).  Grams. 

Crucible  +  BaSOi  11. 126 

Crucible    ii.oii 

BaS04  0.015 

BaS04  :  SO.  ::  0.015  :  x 

X  =  0.0051 

0.0051  X  10  X  100  ^^ 
^    ^^^     ^ =  0.51  per  cent.  SO3. 

Alumina  (50  cc.  from  250  cc.  =  Vs  of  100  cc.  of  original  solution, ) 

Grams. 

Crucible  +  AL-Oa.Fe.Os  12.6614 

Crucible    12.3160 

Al,0..Fe,03    0.3454 


e:ngine:ering  che:mistry 


73 


Fifty  cubic  centimeters  of  the  iron  solution,  in  (4),  by  titration, 
gave  0.58212  gram  of  iron  or  0.3326  gram  of  ferric  oxide  for  50  cc. 
of  the  250  cc.  solution  of  Fe203,Al203  in  (3)  of  the  scheme  on 
page  71.  Subtract  this  weight  (0.3326)  from  the  weight  of 
alumina  and  ferric  oxide  (0.3454)  in  the  50  cc.  The  remainder 
equals  0.0128  gram  alumina. 

0.0128  X  25  X  100  ,  _ 
^    ^  -^ =^  3,20  per  cent.  Al^Og. 

Another  method  of  determination  of  alumina  in  presence  of 
ferric  oxide,  where  the  aluminum  oxide  is  in  small  amount,  is  to 
fuse  the  weighed  oxides  with  potassium  hydroxide  in  a  silver 
capsule,  and  extract  with  water.  The  alumina  forms  a  soluble 
salt  whereas  the  ferric  oxide  remains  undissolved. 

Filter  off  ferric  oxide,  wash,  ignite,  weigh  and  subtract  weight 
from  the  former  weight  of  both  oxides.    Difference  is  the  weight 
of  alumina. 
Manganese  oxide  (100  cc).  Grams. 

Crucible  +  Mn:i04 12.166 

Crucible    12. 131 

Mn304   0.035 

0.035  X  5  X. 00   _  ,  ^5  p,,  ,,„t   Mn30.. 

Lime  (100  cc).  Grams. 

Crucible  +  CaO  8.936 

Crucible    8.929 

CaO 0.007 

0.007  X  5  X  100  ^    ^  ^ 
^  ^^  ^  ^^ =  0.35  per  cent.  CaO. 

Magnesia  ( 100  cc. ).  Grams. 

Crucible  +  Mg.P.Or  8.929 

Crucible 8.919 

MgoPaOi o.oio 

Mg2P207  :  (MgO)2  : :  o.oio  :  x 
X  =  0.0036 

o.oo-iS  X  10  X  100  _  .    ,,  ^ 
^    ^ — =  0.18  per  cent.  MgO. 


74 


e:ngine:icring  chemistry 


Water  of  hydration.  Grams. 

Amount  of  ore  taken 1.267 

CaCl2  tube  +  H-.0 29.065 

CaClo  tube   28.963 

H2O   0.102 

—       C^-" ^  8,05  per  cent.  H.^O  (hydrated.) 

Resume. 
Carbon  dioxide  absent.  Percent. 

Insoluble  mineral  matter   2.50 

AI2O3  3.20 

Fe^Os    ' 83.16 

Mn304   1.75 

P2O5    0.12 

SO3  0.51 

CaO    0.35 

MgO    0.18 

H2O  (hydrated)    8.05 

Total    99.82 


If  the  ore  is  a  magnetite,  the  iron  exists  as  FeO,Fe203.  There 
are  several  methods  of  determining  the  FeO  in  presence  of 
FegOa-     The  one  recommended  by  Whittlesay  and  Wilbur^  is 

1  Chemical  Nervs,  19,  270. 


kngine:e:ring  che:mistry  75 

frequently  used,  but  the  method  of  Allen  is  simpler  and  is  to  be 
preferred.    It  is  as  follows  : 

One  gram  of  the  very  finely  powdered  iron  ore  is  heated  in  a 
small  sealed  combustion  tube,  half  full  of  fuming  hydrochloric 
acid  (25  cc.  of  the  acid  being  sufficient).  The  heating  is  first 
performed  in  the  water-bath  for  2  or  3  hours,  then  in  a  hot-air 
oven  at  150°  C.  for  4  hours  more. 

The  ore  is  thus  completely  decomposed,  and  after  cooling  the 
tube,  it  is  broken  under  water  in  a  beaker,  and  the  ferrous  oxide 
immediately  determined  by  titration  with  standard  solution  of 
potassium  bichromate.  The  amount  of  ferrous  oxide  subtracted 
from  the  total  oxides,  determined  in  another  sample  of  the  ore, 
gives  the  amount  of  ferric  oxide. 

Iron  Ores  Insoluble  in  Acids. 

Some  iron  ores  resist  solution  in  acids  in  which  case  the 
scheme  is  modified  as  follows : 

Two  grams  of  the  finely-pulverized  ore  are  fused  with  15  grams 
of  fusion  mixture  (Na^gCOs  -|-  K2CO3)  in  a  large  platinum 
crucible  for  ^  hour.  After  cooling,  the  fused  mass  is  treated 
with  boiling  water,  the  contents  transferred  to  a  4-inch  porcelain 
capsule,  made  acid  with  hydrochloric  acid  (carefully),  and  evap- 
orated to  dryness,  50  cc.  hydrochloric  acid  added,  warmed  until 
solution  of  iron  is  complete,  then  50  cc.  of  water  added,  and  the 
solution  filtered  from  the  silica,  etc.  The  analysis  can  now  be 
finished  by  scheme  for  iron  ore. 

Determination  of  Chromium  in  Chrome  Iron  Ore.^ 

Take  0.5  gram  of  the  very  finely  divided  mineral  and  inti- 
mately mix  it  with  12  grams  of  a  mixture  containing  equal  parts 
of  dry  sodium  carbonate  and  barium  dioxide  transfer  to  a  large 
platinum  crucible,  and  fuse  over  the  Bunsen  burner  for  J^  hour. 
At  the  end  of  this  time  a  quiet  fusion  is  obtained  and  the  decom- 
position is  completed.  The  crucible  is  placed  in  a  beaker  covered 
with  water,  and  hydrochloric  acid  added,  a  little  at  a  time,  till  the 
mass  is  completely  disintegrated.     The  crucible  is  then  removed, 

1  Process  of  Donath  modified  by  I,.  P.  Kinnicutt  and  G.  W.  Patterson.  J.  Anal.  Chem., 
3,  151- 


76 


ENGINEERING    CHEMISTRY 


the  solution  made  strongly  alkaline  with  caustic  potash,  and  lo  cc. 
of  a  5  per  cent,  solution  of  hydrogen  dioxide  added  to  oxidize 
the  small  amount  of  chromium  sesquioxide  that  may  be  present. 
The  solution  is  now  boiled  for  20  minutes  to  remove  any  excess 
of  hydrogen  dioxide,  made  acid  with  hydrochloric  acid,  and  the 
amount  of  chromic  acid  determined  by  the  aid  of  a  standardized 
solution  of  ferrous  chloride,  i  cc.  of  which  corresponds  to  0.015 
gram  Cro03. 

Reference. 

Consult :    Johnson,  p.  140. 

The  following  analyses  indicate  the  varying  amounts  of  chro- 
mium sesquioxide  in  the  chrome  iron  ores : 


Place 

FeO 

MgO 

CroOg 

ALO3 

SiO,. 

Analyst 

1.  Chester  Co.,  Pa      

2.  Baltimore   Md. 

35.14 
36.54 
18.97 
20.13 

24.00 
25.66 
35.68 
21.28 
8.42 

30.04 
32.93 

34.66 

9.96 
7-45 

5T36 
15.03 
18.13 

6  68 

51.66 
39-51 
44.91 
60.04 

53.00 
54.08 
45.90 
49-75 
64.17 

63.37 
52.13 

63-38 

9.72 
13.00 
13.85 
11.85 

12.00 
9.02 
3.20 
11.30 
10.83 

1-95 
10.S4 

2.09  =    99.61 

10.06=    99.11 

11.82=    98.51 

-    =    99.47 

Mn. 

10.00, 1. 00  =  100. 
4.83=    98.95 

-  =    99.81 

-  =  100.46 

19.91  =  lOI.OI 

Ca. 
2.21,  201  =    99.58 
4.75  =  100.65 
Ni. 

-  =  104.29 

Seybert. 

3.          "            ma.ssive 

4-          "            cryst    

5.  Siberia 

6.  Roraa.s,  Nor 

7.  Bolton,  Ga     .               

8.  I,ake  Memphramagog,  U.  S.  . 

9.  Beresof ,  Sib 

10.  Baltimore,   Md 

11.  Voltena,  Tuscany, 

12.  Texas,  Pa 

Abich. 

Langier. 

Hunt. 

Moberg. 

Rivot. 
Bechi. 

Garret. 

Determination  of  Titanium  in  Iron  Ores. 

The  method  of  BetteU  is  generally  used. 

Fuse  about  0.5  gram  of  the  finely  powdered  ore  with  6  grams 
of  pure  potassium  bisulphate  in  a  platinum  crucible  at  a  gentle 
heat,  carefully  increased  to  redness,  and  continued  till  the  mass 
is  in  tranquil  fusion.  Remove  from  the  source  of  heat,  allow  to 
cool,  digest  for  some  hours  in  150  cc.  of  cold  distilled  water  (not 
more  than  300  cc.  are  to  be  used,  as  it  generally  causes  a  pre- 
cipitation of  some  titanic  acid)  ;  filter  off  from  the  silica,  dilute 
to  1,200  cc,  add  sulphurous  acid  until  all  the  iron  is  reduced, 
then  boil  6  hours,  replacing  the  water  as  it  evaporates. 

1  Crookes,  "Select  Methods,"  p.  194. 


e:ngine;e:ring  che:mistry 


77 


■ 

^^^^P  The  titanic  acid  is  precipitated  as  a  white  powder,  which  is 
^^^^low  filtered  off,  washed  by  decantafion,  a  Httle  sulphuric  acid 
^B  being  added  to  the  wash-water  to  prevent  it  carrying  away  ti- 
tanic acid  in  suspension.  Dry,  ignite,  allow  to  cool,  moisten  with 
solution  of  ammonium  carbonate,  reignite,  and  weigh.  The  ti- 
tanic acid  is  invariably  obtained  as  a  white  powder  with  a  faint 
yellow  tinge,  if  the  process  has  been  properly  carried  out. 


Reference. 

(Iron  Ores.)     "The  Iron  Ores  of  the  United  States."    Proceedings  of  the 
Iron  and  Steel  Institute,  special  volume,  1890,  pp.  68-91. 

Composition  of  Various  Iron  Ores. 


u  o 
ate 


§5 


o      h 


.T5  O 


o  o 


ObO 


FeO.  .... 

Fe^O,  . . . . 

MnO.,  .  . . 

AI2O3  . .  - . 

CaO   

MgO  .... 

SiO,  .... 

CO, 

P2O5  ••.. 

SO3 

H2O. 

TiO.,     . . . 

Cr^Oa-  .. 
{  Organic 
(  Matter 

Total 


90.52 
trace 

1-39 
0.70 
0.42 
4.76 

0.26 
0.05 
1.90 


69-93 

3.12 

1.53 
1.62 

13-45 

0.25 

10.21 


26.52 

63.18 

0.12 

3.28 

0.38 

6.68 

0.05 
o.oi 


20.13 

11.85 

7.45 


60.04 


22.39 

53-71 
0.25 


0.50 


23.72 


45-86 
0.40 
0.96 
5-86 
1-37 
1.S5 
10.88 
31.02 
0.21 
o.io 


0.90 


2.72 
40.77 


0.90 

0.72 

10. 1  2 

26.  41 


17-38 


47-96 
9-50 

3.12 
39-19 


99-47 


100.57 


99.41 


99.02 


99-77 


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ENGINEERING   CHEMISTRY 


79 


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i:ngine:e:ring  chemistry 


THE  METHODS  OF  THE  UNITED  STATES  STEEL  CORPORATION 
FOR  THE  COMMERCIAL  SAMPLING  OF  IRON  ORES.^ 


Iron  Ore  Sampling  in  General. 

Owing  to  the  varying  conditions  under  which  iron  ores  must 
be  sampled,  both  by  the  producer  and  the  consumer,  variations 
from  any  uniform  procedure  of  sampHng  are  necessitated.  The 
elements  of  time,  size  of  shipment,  kind  of  ore  and  other  con- 
siderations are  determining  factors  in  the  details  of  procuring 
the  sample.  Hence  it  is  the  purpose  to  render  the  following 
methods  general  in  their  scope,  promulgating  those  ideas  appli- 
cable in  the  broader  sense  to  ore  sampling,  without  attempting 
to  prescribe  for  ever  varying  and  unforeseen  contingencies  in  the 
details. 

Car  Sampling  at  Producer's  End. 

All  samples  must  be  taken  uniformly  over  the  surface  of  the 
cars  after  being  loaded  by  taking  a  minimum  of  twelve  places  for 
wooden,  and  fifteen  places  for  steel  cars,^  by  either  the  parallel  or 
the  zigzag  system.  The  following  diagrams  illustrate  these  two 
systems  and  show  the  minimum  number  of  points  where  samples 
are  to  be  taken. 

PARALLEI*  SYSTEM. 

'25  TON  WOODEN  CAR.  50  TON  STEEL  CAR. 


o  o  o  e 

o  «  o  o 

o  e  o  o 


ZIGZAG  SYSTEM. 

25  TON  WOODEN  CAR.  SO  TON  STEE^L  CAR. 


O  O     o 

o  e  o 

o  o  o 


Figs.   9   and    lo. 

^  Copyright  1908  by  J.  M.  Camp.     Reprinted  by  permission. 

2  At  the  producer's  end,  the  mines,  there  are  two  types  of  cars  in  use.  The 
wooden  car,  rapidly  being  displaced  by  the  all  steel  car,  especially  built  for  the  pur- 
pose, contains  25  tons  of  ore  when  full  to  overflowing,  and  the  all  steel  car,  men- 
tioned above,  smaller  than  the  standard  car  holding  50  tons  when  full. 


i:ngine:e:ring  chemistry 


8i 


When  lumps  of  ore  are  encountered  at  the  designated  points 
where  samples  are  to  be  taken,  small  portions  of  each  lump  must 
be  chipped  off,  about  equal  in  size  to  the  first  joint  of  the  thiimb. 
When  rock  occtirs  it  must  also  be  sampled  as  ore,  that  is,  a  pro- 
portionate amount  of  the  rock  or  off  grade  material  is  to  be 
taken,  not  equal  in  amount  to  the  regular  sample  for  the  area 
covered  by  that  point,  unless  the  entire  area  is  such  off  grade 
material.  Then  the  same  amount  of  adjacent  material  must  be 
taken,  ore  or  rock,  equal  in  amount  to  the  portion  taken  at  each 
regular  point.  This  also  applies  to  field  boulders,  unless  thrown 
from  cars. 

The  samples  are  taken  with  a  garden  trowel.  Each  lo  cars, 
either  steel  or  wooden,  must  be  combined,  as  a  rule,  into  i  sam- 
ple; but  less  than  lo  cars  may  be  grouped.  The  weight  of  the 
sample  must  not  run  under  15  pounds  for  10  wooden,  and  20 
pounds  for  10  steel  cars. 

Whenever  very  lumpy  ore  is  to  be  sampled  in  the  cars,  the  rope 
net  system  is  used  as  shown  below,  which  gives  about  thirty-two 
places  on  each  car,  the  knots  being  18  inches  apart.  "  In  using  the 
net  system,  if  a  lump  of  ore  or  rock  comes  directly  under  the  knot, 
a  piece  should  be  taken  about  the  size  of  the  first  joint  of  the 
thumb.  If  fine  ore  occurs  under  a  knot,  an  equal  amount  is 
taken  with  the  trowel.  The  rope  net  system  is  used  at  the  Mar- 
quette Range  on  the  hard,  lump  ore;  also  at  the  Soudan  Mine, 
Vermilion  Range. 


] 

Rope  Net  System. 

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Fig.    II. 


82  Kngine:e:ring  chemistry 

A  moisture  must  be  taken  for  each  train  load  from  all 
open  pit  mines;  a  train  consists  of  40  to  45  of  the  50-ton  steel 
cars,  or  60  to  68  of  the  25-ton  wooden  cars.  A  moisture  sample 
must  also  be  taken  for  all  the  cars  loaded  as  a  shaft  or  stockpile 
during  each  lo-hour  shift.  Samples  must  be  taken  from  three 
places  on  top  of  each  car  as  shown  by  the  following  diagram. 


Fig.    12. 

Care  should  be  taken  to  secure  the  sample  from  well  under- 
neath the  surface  as  soon  as  practicable  after  loading,  maintain- 
ing the  true  proportion  of  lump  and  fine  ore.  The  sample  as 
taken  must  be  immediately  placed  in  a  can  with  a  tightly  fitting 
lid,  and  brought  to  the  crusher  house.  It  is  optional  to  take  a 
moisture  sample  from  the  regular  sample,  provided  it  has  been 
taken  from  well  underneath  the  surface. 

Cargo  Sampling  at  Consumer's  End. 

Cargo  ores  present  the  most  serious  obstacles  to  a  uniform 
method  of  sampling.  The  boats  vary  in  size  from  3,000  to  12,000 
tons  with  I  or  2  decks,  and  in  the  number  of  hatches  from  6  to 
36  widths  varying  from  12  to  24  feet.  The  grabs  at  the  different 
unloading  points  vary  in  number,  kind,  size,  and  the  rapidity  of 
their  operation.  The  ores  vary  from  the  very  fine  to  the  all 
lump,  from  the  so-called  mixed  ores  such  as  the  groups  to  the 
mixed  cargoes,  consisting  of  different  ores  in  the  same  boat,  and 
with  different  ways  of  loading  boats. 

Grab  Sampling. — An  excellent  method  of  cargo  sampling 
where  the  entire  cargo  will  be  represented,  and  particularly  adapt- 
able for  fine  ores.  A  sampler  with  a  small  scoop  attached  to  a 
handle  of  suitable  length  and  holding  a  definite  amount  of  ore, 
a  quarter,  a  half  or  a  whole  pound,  takes  a  scoopful  from  each 


kngine:e:ring  che:mistry 


83 


grab  as  it  rises  above  the  deck.  The  disadvantage  of  this  system 
is  its  increased  cost  due  to  the  extra  number  of  samplers,  one 
being  required  for  each  grab  during  the  entire  time  of  unloading. 
The  general  plan  for  the  sampling  of  all  cargoes  is  to  first 
sample  the  tops  of  the  piles,  before  the  grabs  have  started  to 
unload;  this  is  called  sampling  of  the  cones.  After  the  grab 
has  removed  from  the  hatch  all  the  ore  v^ithin  reach,  the  ex- 
posed faces  standing  on  each  side  are  sampled;  this  method  is 
known  as  face  sampling.  Or  when  the  latter  practice  is  im- 
practicable owing  to  the  operation  of  the  grabs,  then  the  method 
of  rounds  is  followed. 

In  sampling  a  small  shovel  or  garden  trowel  is  used,  the  total 
length  of  which,  including  the  handle,  is  12  inches,  and  it  also 
constitutes  a  measure.  It  is  the  aim  to  take  equal  sized  samples 
from  each  of  the  points  selected.  When  lump  ore  or  rock  is  en- 
countered at  the  point  determined  by  the  measure  a  portion  is 
broken  off  equal  to  the  amount  regularly  taken. 

In  the  sampling  of  the  cones,  at  a  point  midway  between  the 
side  and  the  center  of  the  boat,  directly  under  the  edge  of  the 
hatch,  the  first  sample  is  taken  and  sampling  continued  i 
shovel  length  apart  up  the  surface  of  the  cone,  over  its  apex 
and  down  the  opposite  surface  to  a  corresponding  point  under 
the  other  edge  of  the  hatch.  This  line  is  crossed  from  corres- 
ponding opposite  points  under  the  hatch  as  shown  in  the  follow- 
ing sketch.  Not  more  than  one-tenth  of  the  total  sample  is  to  be 
taken  in  the  sampling  of  the  cones. 

CONE  SAMPLING. 
HATCH. 


///•V/;'-^\\V  \\ 


Fig.    13. 


84 


ENGINEKRING    CHEMISTRY 


Face  Sampling. — After  a  grab  has  removed  from  a  hatch  all 
the  ore  within  reach  and  has  moved  to  another  hatch,  the  sam- 
pler shall  measure  2  shovel  lengths  from  the  side  of  the  boat  and 
start  up  the  exposed  face  of  the  ore,  taking  samples  i  shovel 
length  apart  all  the  way  to  the  top,  using  a  ladder  if  necessary. 
The  next  vertical  line  is  measured  4  shovel  lengths  from  the  first 
and  the  samples  taken  each  shovel  length  apart  on  this  line  as  be- 
fore and  so  on  for  each  succeeding  line  across  the  boat.  This  is  re- 
peated on  the  opposite  ore  face,  and  the  entire  procedure  con- 
tinued until  the  ore  faces  of  all  the  hatches  are  sampled  that  the 
character  of  the  boat  and  the  operation  of  the  grabs  will  permit. 
When  a  bulkhead  occurs  only  the  face  opposite  to  it  is  to  be 
sampled. 

FACE  SAMPLING. 


DECK. 


Round  Sampling. — When  the  operation  of  the  grabs  makes 
sampling  by  the  face  method  impracticable,  or  with  boats  having 
24-foot  hatch  centers,  and  decks  furnishing  protection  to  the 
samplers,  then  sampling  shall  be  done  while  the  ore  is  being  re- 
moved by  the  grabs.  When  5  or  6  feet  of  the  face  of  the  ore 
have  been  exposed,  the  sampler  shall  enter  the  hatch  and  meas- 
uring 2  shovel  lengths  from  the  side  of  the  boat  or  edge  of  the 
face,  take  successive  samples  up  the  face  i  shovel  length  apart. 
The  next  vertical  line  is  measured  ■  4  shovel  lengths  from  the 
first,  and  samples  are  taken  all  the  way  to  the  top  as  before,  and 
so  on  across  the  entire  face  of  the  ore.  This  procedure  is  re- 
peated on  the  opposite  face,  one-third  of  the  total  weight  of  the 


KNGINEKRING    CHEMISTRY  85 

sample  to  be  taken  in  the  first  round.  When  all  the  ore  within 
reach  of  the  grab  is  removed,  the  second  round  is  taken,  using  the 
measurements  as  above,  and  the  remaining  two-thirds  of  the  sam- 
ple are  secured. 

Part  of  the  regular  sample  is  to  be  taken  for  the  moisture  sam- 
ple, and  for  the  fineness  sample  when  such  is  desired. 

Car  Sampling  at  Consumer's  End. 

When  the  ore  is  received  in  cars  the  greatest  possible  number 
are  represented  in  the  samples,  and  not  less  than  lo  equal  sized 
samples  are  taken  from  each  car.  When  cars  are  loaded  with 
fine  ore  with  the  piles  in  opposite  ends,  at  least  5  samples  are 
taken  from  each  pile,  the  first  one  at  the  apex  of  the  pile,  and  the 
other  4  at  points  symmetrically  arranged  around  the  sides  of  the 
pile,  two-thirds  of  the  distance  from  the  apex  to  the  base  of  the 
pile  or  sides  of  the  car.  With  cars  loaded  in  the  center,  the  system 
is  the  same,  except  that  the  center  of  the  side  of  the  pile  length- 
wise of  the  car,  is  the  first  point,  the  other  four  being  symmetri- 
cally arranged  around  this  point. 

When  the  10  points  are  located  in  a  car,  each  of  them  is  sup- 
posed to  represent  a  definite  area,  equal  to  one-tenth  of  the  ore 
surface  of  the  car.  If  the  car  contains  all  fine  ore,  then  10  equal 
sized  samples  are  taken,  one  from  each  of  the  points.  If  the  car 
contains  a  mixture  of  fine  and  lump  ore,  with  varying  amounts 
of  each  in  the  areas  included  in  the  different  divisions,  then  each 
area  is  judged  separately  and  sampled  accordingly.  The  fine 
and  lump  ore  are  taken  each  in  its  proper  proportion,  the  former 
with  the  trowel,  the  latter  being  chipped,  or  selected  small  pieces 
being  taken,  each  about  the  size  of  the  first  joint  of  the  thumb. 
The  combined  sample  of  fine,  chipped  and  selected  pieces  from 
each  area,  equals  the  amount  taken  were  it  all  fine  ore.  If  the  con- 
tents of  the  car  are  all  lump  ore,  the  proper  sized  pieces  are  chipped 
from  four  or  five  of  the  lumps  in  each  of  the  10  areas  making 
40  or  50  pieces  from  each  car,  the  total  amount  of  chipped  pieces 
from  each  of  the  areas  equalling  the  amount  that  would  be  taken 
were  it  all  fine  ore.  All  samples  of  fine  ore  are  taken  from 
well  underneath  the  surface  to  obtain  the  ore  in  its  natural  state. 


86  e:ngine:e:ring  che:mistry 

A  proportionate  amount  of  the  main  sample  is  retained  in  a 
tightly  closed  can  for  the  moisture  determination. 

Preparation  of  Samples  in  General. 
In  the  preparation  of  the  sample  for  analysis,  the  ideal  prac- 
tice is  to  crush  and  quarter  alternately  until  the  desired  quantity 
with  the  requisite  degree  of  fineness  is  attained.  A  more  ex- 
peditious and  equally  efficient  method,  is  to  crush  the  entire 
sample  to  the  desired  degree  of  comminution,  then  reduce  the 
quantity  by  successive  quartering  as  before,  until  the  desired 
amount  remains.  It  should  ever  be  our  purpose  to  approach  as 
closely  as  possible  to  either  of  these  two  methods  in  the  prepara- 
tion of  all  samples  for  analysis. 

Preparation  of  Sample  at  Producer's  End. 

Samples  before  being  quartered  are  brought  into  the  crusher 
house  where  they  are  dried,  if  necessary,  at  ioo°  C.  until  the  ore 
can  be  well  mixed.  Care  must  be  taken  to  prevent  over  heating 
when  other  than  low  pressure  steam  is  used  for  the  purpose,  es- 
pecially with  ores  containing  a  large  quantity  of  limonite.  When 
sufficiently  dry  the  larger  lumps  are  crushed,  if  necessary,  so 
that  the  entire  sample  will  pass  through  a  3^-inch  mesh  sieve;  a 
finer  sieve  may  be  used  if  desired.  The  sample  is  thoroughly 
mixed  on  an  iron  top  table,  then  spread  out  evenly  about  ^  of 
an  inch  in  depth  and  alternately  quartered  and  mixed  until  %  of 
the  original  sample  remains.  It  is  now  crushed  until  fine  enough 
to  pass  a  ^-inch  mesh  sieve,  then  mixed  and  quartered  as  before 
until  about  2  pounds  remain.  It  is  again  crushed  until  fine 
enough  to  pass  a  20-mesh  sieve,  and  spread  out  evenly  about  ^ 
of  an  inch  in  depth.  About  3  ounces  of  this  are  taken  from  all 
over  the  pile,  with  a  small  spatula,  dried  in  a  small  pan  at  100°  C. 
and  crushed  on  a  chrome  steel  plate,  until  it  will  pass  through 
a  lOO-mesh  sieve.  After  being  thoroughly  mixed  this  is  trans- 
ferred to  a  bottle,  and  constitutes  the  sample  for  analysis. 

The  following  method  for  the  preparation  of  the  sample  is 
optional.  All  the  ore  is  passed  through  a  ^-inch  sieve,  thor- 
oughly mixed  on  a   suitable  cloth  and   quartered  in  the  usual 


Engine:e:ring  chemistry  %y 

way,  diagonally  opposite  portions  being  rejected  until  about  5 
pounds  remain.  The  sample  is  again  crushed,  if  need  be,  to 
pass  a  ^-inch  mesh  sieve,  and  mixed  and  quartered  as  before 
until  1^/2  to  2  pounds  remain.  After  being  dried  at  100°  C.  for 
20  to  30  minutes,  it  is  crushed  to  a  fineness  of  20-mesh,  mixed 
and  quartered  until  about  3  ounces  remain,  and  the  entire  sam- 
ple is  crushed  on  a  chrome  steel  plate  and  passed  through  a  100- 
mesh  sieve.  The  sample  is  spread  out  in  a  shallow  pan,  dried 
at  100°  C.  for  30  minutes,  again  mixed  and  transferred  to  a 
3-ounce  bottle  or  can  for  the  analysis. 

Preparation  of  Sample  at  Consumer's  End. 

The  aggregate  sample  is  dried  at  100°  C.  and  crushed  before 
any  quartering  whatsoever,  so  that  the  entire  mass  will  pass 
through  a  ^-inch  mesh  sieve.  This  is  reduced  by  successive 
quartering  and  crushing  until  its  weight  is  from  4  to  8  ounces, 
and  it  will  then  all  pass  through  an  8-inch  mesh  sieve.  Or  the 
entire  sample  is  crushed  so  it  will  pass  through  an  8-inch  mesh 
sieve,  and  then  quartered  as  before  until  from  4  to  8  ounces 
remain.  And  this  final  quantity  is  then  further  crushed  with  a 
chrome  steel  bucking  board  and  muller  and  all  passed  through 
a  loo-mesh  sieve.  A  sufficient  amount  of  this  powder  for 
all  the  needs  of  the  analyst  is  placed  in  a  small  air-tight  con- 
tainer, dried  for  i  hour  at  100°  C.  and  when  cool  it  constitutes 
the  sample  for  analysis.  A  separate,  larger  portion  of  the  same 
sample  is  retained  for  further  needs. 

Resume:. 

Per  cent. 

Lime    (CaO)    36.46 

Magnesia  (MgO)    2.12 

Silica   (SiOO    43-25 

Alumina    (AI2O3)    15.94 

Ferrous  oxide  (FeO) 0.31 

Sulphur  (S)   1.53 

Manganese  oxide  (Mn02) o.io 

Phosphoric  acid   (P2O3) 0.09 

Undetermined    0.20 

Total   100.00 


ENGINEERING   CHEMISTRY 


a       w  2 
Z  8  c  1: 

^     t-     i)     V 


.t:  "o 
a  * 

a  i; 
.2  ^ 

W    J2 


Sg 


c  5 

^  .5 

c 


O-Og 


'O  rs  -;: 


>-  i:  o 
o  cd  j: 

2  ^ ;:: 

p   u    c 

>.  8  .i^ 

_    -  * 


t  P  8 


-5  :g  -g 


ii  i;  -M 


It 


O 
2     01 


CI    "^    f— i 


ii   S    rt 
3    rt    o 


O   73   .- 

C  .5  S 

c  £  ^ 

o  2  X 

y  a  "S 


g   o  o  >  j^ 

2  <t»  i  c 

?  p  p  o  JH 

^  rt  v^  2 

a.  ^  cs  be 


CiihH 

o2o^ 

4 

a°S 

Crucible  +  BaS04  =  11.92356  grams. 

B 

—      =  11.879 

aS04  =  0.04456 

CO 

S  =  1.53  per  cent. 

'1 

'_H  -0  5  c  cfl 

«;'  ^"^-^s 

>.•-_!. '^•O 

-vr,  ^^ 

5'^  It  c        Crucible  +  Mg2P207  =  11.90253  grams 

■ 

earl 
filte 
lefi 
ps  0 
tere 

-a  °'0  to 

:   HoO,  make  solution  n 
idd  NaCoHgOo,  boil  and 
ron  and  aluminum.     Tl 
250  cc.  flask,  a  few  dro 
e  twelve  hours,  then  fil 

"Z     •;;  tr.  .3                               MgoPoOr  =    0.02353 

d 

^  4;     .-  «           MgaPgO;  :'(MgO)o  :  :  0.02353  :  ^ 

•  |5-2^d               ^  =  0.00843 

S  2-S.^Z^D.  0  00843  X  5  X  100                         .  „  ^ 
Sg-C^coaj                 2                -2.13  per  cent.  MgO. 

fa      cu  JicoZ 

be 

.^  *                   Crucible  +  CaO  =  12.02484  grams. 

c^                         •♦              -    =11.87900       " 

v.-^-B 

«  i5  £  =  >."s 

<u    *     g                                           CaO  =    0.14584 

.g  q  >;t*  .0.14584x5X100      ^  , 

•1  uS-cO                 ,   =  36.46  per  cent.  CaO. 

0 
cs 

MgO. 
..  add  100 
h  NaoCOg 
oxides  oi 
iferred  to 
led,  set  as 

(S       cocoSr: 

(J 

ii  «rtO               Crucible  +  Mn304  =  11.87936  grams. 

CaO, 

50  cc 
le  wit 
rated 

trans 
le  add 
iShed, 

^         'Scoo                                      Mn304  =    000036 

d 

-j^-='^---pi 

s    «j;;^(^(i(                0.00036  Mn304  =  0.00041  Mn02. 

•-  0  i-_,T)rt     0.00041  X  5  X  100 

gsp'gc^     3^ — -^-^ =  o.io- per  cent.  MnOg. 

«  S      coSo 

n 

g        rt  0  ZX^  CO 

-a 'g 

Crucible  +  AlsOg+FeaOg  ==  11.94415  grams. 

S  « 

1  Subtract  FeoOg           )          „  ^„„        .. 
1  found  by  titration     /  =    °°"i39 

9. 

^<  . 

Crucible  +  AI2O3  =  11.94276        " 

-53 

Crucible  =  11.8790         " 

A^l§ 

AI0O3  =  0.006376        " 

< 

6  r2  ii  .i: 

0.006376  X  5  :^  100                              .    . ,  ^ 

3  "1.5 

^ =  15.94  per  cent.  AloOg. 

rt  S  «•=  i"^  « ,■"                                     50  cc.  require  0.058  cc,  KgCroOT  solution. 

""^      nO^      - 

"^                                     I  cc.  K-jCroO:  solution  =  0.0168  eram  Fe. 

«u  d  S-=  co-tio'c                                    50  cc.  solution  of  slag  =  0.000974   "      " 

C  0.2 .ti  a;-- 

£•                                        250CC.                          "     =0.004870   "      " 

6 

°o3&.5^CJ4i               Fe  .  FeO  ::  0.00487  :  ;r 

^ 

<u  "^0  D  S  c  L^  «                          ^  =  0.0062 

^t^  w  0  I-  0 

..  3            0.0062  X  100 

d^4;o'af-iii                    .            -  0.31  per  cent.  FeO. 

^^-a.ev.a'z 

>,  CO                         ^ 

sam- 

from 

1     and 

sphor- 

rected 

Crucible  +  MgaPgOr  =  11.00935  grams. 

"                —        =  11.00879       '* 

one 
50  cc. 
lutioii 
r  pho; 
as  di 
ore 

MgoPoOy  =  0.00056 

MgoPoO;  .  P2O5  •  .  0.00056  :  :r 

0 

^u^  g-^-oS 

X  =  0.0003594 

0  CO  °      t?  y  C 
0  H  (u  w  2  ca- 

0.0003594  X  5  X  too                              ^    ^  ^ 
^^^^ — ^— =  0.09  per  cent.  P0O5 

cu     aSS.y.? 

. 

0  ^S 

■«»  -^^ 

Crucible  +  SiOo  =  17.585  gr^ms. 

.^-S 

"                 —    =  16.720 

-§   ^^  ..       0.8 

SiOo  =    0.865 

6* 

ci5 

65     X      100                                                                          ^        r.-^ 

-^ =  43-25  per  cent.  SiOo. 

«       rt':2 

ENGINEERING   CHEMISTRY 


89 


Form  of  Bi.ank  Used  for  Reporting  Blast-Furnace  Si^ag  Anai^yses. 

S1.AG. 


j)ate   

Orf^  impri 

"^Jr>    nf  irnn  ....  .... 

Lime  ( CaO ) • 

...    . . 

Silica  (SiOg) 

Oxide  of  iron  ( FeO ) 

Calcium  sulphide  (CaS) 

' 

Examples  of  Blast-Furnace  Slag  Analyses. 


FeO 

SiOa 

AI2O3 

CaO 

MgO 

MnO.,    

Sulphur  f  sulphide  of  1 
Calcium  \  calcium  j 
Phosphoric  acid  (P2O5)  • 
Undetermined  loss 


No.  i.i 

No.  2.2 

Per  cent. 

Per  cent. 

0.270 

0.436 

45.460 

35.000 

16.590 

14.362 

32.805 

45-370 

1.080 

1-398 

0.083 

trace 

I.571 

1.875 

1-963 

1.500 

0.008 

0.059 

1. 1 70 

— 

100.000 

100.000 

Some  varieties  of  slag  are  soluble  in  hydrochloric  acid,  in 
which  case  the  solution  can  be  made  in  HCl.  This  applies  also 
to  open-hearth  slags,  refinery  slag,  tap-cinder,  mill-cinder  and 
converter  slag. 

1  Slag  made  during  the  run  of  Alice  Furnace,  on  mixture  containing  Enterprise  ore. 
-  Slag  made  at  the  Sloss  Furnace  in  June,   1886,   on  No.   i   foundry  iron.     (Consult 
Trans.  A.I.  M.  E.,  16,  p.  148.) 


90  ENGINEERING   CHEMISTRY 

Basic  slags,  from  the  Thomas-Bessemer  process,  often  con- 
tain over  20  per  cent,  of  phosphoric  acid  and  require  a  some- 
what different  process  of  analysis.     Thus: 

One  gram  of  the  finely  pulverized  slag  is  fused  with  excess 
of  sodium  carbonate  in  a  platinum  crucible.  Extract  with  water, 
acidify  the  solution  with  nitric  acid  and  evaporate  in  a  porcelain 
dish  to  dryness.  Take  up  with  hydrochloric  acid,  dilute  to  Y^ 
a  liter,  and  precipitate  the  phosphoric  acid  by  the  acetate  process. 

The  precipitate  is  filtered,  dissolved  in  hydrochloric  acid,  ex- 
cess of  nitric  acid  added,  and  the  solution  concentrated  until  the 
hydrochloric  and  acetic  acids  are  expelled.  The  nitric  acid  so- 
lution is  diluted  to  500  cc.  and  two  portions  are  taken  (each 
250  cc.)  and  the  phosphoric  acid  determined  in  these  by  the 
molybdate  method. 


THE  FORD-WULIAMS  METHOD  FOR  HIGH  GRADE 
MANGANESE  ORES. 


Ores  in  Which  all  of  the  Manganese  is  Soluble  in  HCl. — 
Weigh  0.5  gram  of  finely  powdered  ore,  transfer  to  No.  4  beaker, 
and  add  20  cc.  HCl.  Digest  until  residue  is  white  and  flotant, 
evaporate  to  a  syrup,  add  no  cc.  strong  HNOj  and  boil  until 
red  fumes  are  nearly  gone.  Now  add  ^  teaspoonful  of  fine  as- 
bestos fiber  using  care  so  as  to  prevent  boiling  over.  All  red 
fumes  will  disappear  in  about  i  minute  after  adding  asbestos. 
Continue  boiling,  add  8  grams  KCIO3,  boil  10  minutes  longer, 
remove  from  the  source  of  heat,  allow  to  settle  and  filter,  using 
an  asbestos  filter.    Wash  as  in  the  original  method. 

Weigh  0.750  gram  of  C.  P.  oxalic  acid,  dissolve  in  hot  water 
in  a  small  beaker  and  transfer  this  solution  to  the  beaker  in 
which  the  MnO^  was  precipitated.  Add  50  cc.  of  warm  dilute 
H2S04>  dilute  with  warm  water  to  200  cc. ;  and  drop  in  the 
asbestos  filter  containing  the  MnO,2  precipitate.  Stir  and  heat 
gently  (not  above  80°  C.  until  all  Mn02  is  dissolved.  Titrate 
the  solution  with  standard  KMnO^.  Also  titrate  0.750  gram 
oxalic  acid  with  the  same  KMn04.     Subtract  from  this  value  the 


i:ngine:e:ring  chemistry  91 

number  of  cubic  centimeters  used  in  the  first  titration.  The  differ- 
ence is  equal  to  the  KMn04  equivalent  to  the  manganese  in  the  ore. 
Knowing  the  iron  value  of  the  KMnO^,  we  can  calculate  its  man- 
ganese value,  for  Fe  value  X  ^^/ii2  =  Mn  value.  Multiply  differ- 
ence between  first  and  second  titrations  by  Mn  value  of  KMn04 
and  this  result  by  200,  which  gives  percentage  Mn  in  ore. 

Where  all  of  the  Manganese  of  the  Ore  is  not  Soluble  in  HCl, 
filter  from  this  residue  and  evaporate  the  main  solution.  In  the 
meantime  treat  the  residue  with  HFl  and  a  few  drops  of  H2SO4. 
Evaporate  off  the  HFl,  add  a  little  HCl,  heat  until  dissolved 
and  add  to  the  main  solution.  Proceed  as  in  the  case  of  ore  in 
which  all  manganese  is  soluble  in  HCl. 

This  method  gives  results  checikng  well  with  the  phosphate 
method. — /.  Jas.  Skinner,  Chemist,  Longdale  Iron  Co.,  Virginia. 


PROVISIONAL  METHODS  FOR  COPPER,  LEAD  AND  ZINC  OF 
THE  COMMITTEE  ON  UNIFORMITY  IN  TECHNICAL  ANALY- 
SIS OF  THE  WESTERN  ASSOCIATION  OF  THE  TECHNICAL 
CHEMISTS  AND  METALLURGISTS. 


The  Determination  of  Copper. 

Solutions. — I.  A  solution  of  sodium  thiosulphate ;  20  grams  of 
the  salt  in  i  liter  of  water. 

2.  A  solution  of  starch;  made  by  shaking  up  i  gram  of 
finely  powdered  starch  in  a  few  cc.  of  water  and  pouring  it 
into  200  cc.  of  boiling  water.  This  should  be  made  fresh  every 
few  days. 

3.  A  solution  of  potassium  iodide  containing  300  grams  to  the 
liter. 

Standardization. — Dissolve  0.2  to  0.5  gram  of  copper  foil  in 
5  cc.  of  nitric  acid  and  evaporate  to  2  or  3  cc.  Add  5  cc.  of  hot 
water  and  6  cc.  of  ammonia.  Boil  a  few  minutes  and  cool. 
Dilute  to  75  or  80  cc,  add  8  cc.  of  acetic  acid  and  10  cc.  of  the 
potassium  iodide  solution.  Shake  until  all  the  copper  is  pre- 
cipitated and  titrate  the  free  iodine  as  follows :    The  thiosulphate 


92  ENGINEERING    CHEMISTRY 

is  run  in  until  the  brown  of  the  iodine  changes  to  yellow ;  then 
add  4  or  5  cc.  of  the  starch  solution  and  carefully  run  in  more 
thiosulphate  until  the  blue  caused  by  the  starch  disappears,  when 
the  titration  is  finished. 

Copper  in  Ores. — Dissolve  0.5  gram  of  ore  in  2  cc.  of  nitric 
acid,  3  cc.  of  hydrochloric  and  4  cc.  of  sulphuric  acid.  Evap- 
orate to  copious  white  fumes.  Cool  and  take  up  with  25  cc.  of 
cold  water.  Add  a  piece  of  sheet  aluminum  and  boil  until  all  the 
copper  is  precipitated.  Add  10  cc.  of  hydrogen  sulphide  water  to 
insure  complete  precipitation  of  the  copper.^  Filter,  washing 
three  times  by  decantation.  Pour  55  cc.  strong  nitric  acid  over 
the  aluminum  and  copper.  Remove  the  aluminum  and  wash  with 
a  minimum  hot  water.  Place  the  beaker  under  the  filter  and 
pour  strong  bromine  water  over  the  same  to  dissolve  any  copper 
or  sulphide  of  copper  that  may  run  over.  Wash  with  hot  water 
and  evaporate  the  solution  to  2  or  3  cc.  Add  5  cc.  of  hot  water, 
6  cc.  of  strong  ammonia  and  boil.  Add  8  cc.  of  acetic  acid  and 
10  cc.  of  the  potassium  iodide  solution.  Shake  until  all  the 
copper  is  precipitated  and  titrate. 

The  Determination  of  Lead. 

Solutions. — A  solution  of  ammonium  molybdate  containing 
8.64  grams  of  the  molybdate  to  the  liter. 

A  solution  of  ammonium  acetate  containing  200  grams  to  the 
liter. 

A  solution  of  tannic  acid  containing  i  part  of  the  acid  in  300 
parts  of  water.     This  should  be  made  fresh  every  few  days. 

Standardization. — Dissolve  2  pieces  of  pure  lead  foil  weighing 
about  0.3  and  0.5  gram  respectively  in  10  to  15  cc.  of  (i  :  i) 
nitric  acid.  When  the  lead  is  dissolved  add  20  cc.  of  (i  :  i) 
sulphuric  acid.  Stir  thoroughly  and  allow  to  settle.  Decant  on 
the  filter-paper  and  wash  by  decantation  three  or  four  times  with 
water  containing  2  per  cent,  sulphuric  acid,  always  decanting  as 
closely  as  possible.    Wash  once  with  a  little  cold  water,  keeping 

^  The  copper  is  not  generally  precipitated  completely  by  aluminum,  hence  the  need 
of  hydrogen  sulphide  water.  Arsenic  and  antimony  are  precipitated  by  the  hydrogen 
sulphide  water,   and   are   oxidized  by  bromine,   otherwise   the   results   would   be   high. 


Kngine:e:ring  chemistry  93 


I 

I^B^as  much  of  the  precipitate  in  the  beaker  as  possible.  Dissolve  the 
I^V  lead  sulphate  that  is  on  the  filter-paper  by  pouring  over  it  50  cc.  of 
the  hot  ammonium  acetate  solution.  Pass  this  solution  through 
the  filter  a  second  or  third  time  if  necessary,  then  wash  the  paper 
with  hot  w^ater.  Pour  the  hot  ammonium  acetate  over  the  main 
bulk  of  the  precipitate.  Heat  until  this  is  dissolved,  dilute  to 
200  cc,  make  barely  acid  with  acetic  acid,  and  titrate. 

Titration. — The  ammonium  molybdate  is  run  in  with  constant 
stirring,  testing  from  time  to  time  by  placing  a  drop  of  the  solu- 
tion upon  a  drop  of  the  tannic  acid  solution  on  a  spot  plate.  When 
this  gives  a  yellow  color  the  titration  is  finished. 

Lead  in  Ores. — Dissolve  0.5  to  i.o  gram  of  ore  in  10  cc.  of 
strong  nitric,  then  add  10  cc.  of  strong  sulphuric  acid.  Evap- 
orate to  white  fumes,  cool,  dilute  to  50  cc,  and  boil.  Decant  on 
the  filter-paper  and  wash  by  decantation  3  or  4  times  with  hot 
water  containing  2  per  cent,  sulphuric  acid,  then  once  with  a 
little  cold  water.  Now,  with  the  aid  of  the  wash-bottle,  transfer 
the  sulphates  from  the  filter  back  to  the  beaker,  add  50  cc.  of 
ammonium  acetate  solution  and  boil  thoroughly.^  Filter  again 
through  the  original  filter,  wash  with  hot  water,  make  the  filtrate 
slightly  acid  with  acetic  acid,  and  titrate. 

The  Determination  of  Zinc. 

Solutions  Required. — A  solution  of  ammonium  chloride  made 
by  dissolving  60  grams  of  the  salt  in  250  cc  of  water  and  adding 
150  cc.  of  strong  ammonia. 

A  solution  of  potassium  ferrocyanide,  21.6  grams  of  the  pure 
salt  to  the  liter. 

A  solution  of  uranium  acetate,  4.5  grams  to  100  cc.  of  water 
and  2  cc  of  acetic  acid. 

A  saturated  solution  of  potassium  chlorate  in  nitric  acid. 

Standardization. — Dissolve  0.2  to  0.3  gram  of  freshly  ignited 
zinc  oxide  in  10  cc.  of  hydrochloric  acid,  make  just  neutral  with 
ammonia.     Add  6  cc.  of  concentrated  hydrochloric  acid,  dilute 

1  This  procedure  is  necessary  on  account  of  the  fact  that  lead  sulphate  is  not  readily 
soluble  in  ammonium  acetate  when  other  sulphates  such  as  barium  and  calcium  are 
present. 


94  KNGINKE^RING    CHE:mISTRY 

to  i8o  cc.  with  water,  boil  and  filter.     Check,  using  C.  P.  zinc 
instead  of  zinc  oxide. 

Titration. — Dissolve  the  solution  into  two  equal  parts  and 
quickly  titrate  one  part,  then  add  the  remainder  and  quickly  run  in 
enough  to  almost  finish  the  titration,  then  add  2  drops  at  a  time, 
testing  after  each  addition  by  placing  a  drop  of  the  solution  upon 
a  drop  of  the  uranium  acetate  on  a  spot  plate.  When  this  gives 
a  yellow  color  the  titration  is  finished.^ 

Zinc  in  Ores. — Dissolve  0.5  to  i.o  gram,  according  to  the  rich- 
ness of  the  ore,  in  4  to  8  cc.  of  hydrochloric  and  an  equal  amount 
of  nitric  acid.  Evaporate  to  one-third  of  the  original  volume.  If 
gelatinous  silica  is  present  dilute  a  little  and  filter.^  Add  15  cc.  of 
the  solution  of  potassium  chlorate  in  nitric  acid. 

Evaporate  to  dryness,  but  do  not  bake,^  cool,  add  40  cc.  of  the 
ammonium  chloride  solution  and  boil,  being  sure  that  all  clots 
are  broken  up.  Filter  and  wash  with  hot  solution  of  ammonium 
chloride.  If  much  iron  is  present  the  precipitate  should  be  dis- 
solved in  a  minimum  of  hot  dilute  (1:3)  hydrochloric  acid,  and 
the  treatment  with  ammonium  chloride  solution  repeated.* 

Neutralize  the  filtrate  and  add  15  cc.  of  strong  hydrochloric 
acid,  15  grams  of  granulated  lead,  boil  until  all  copper  is  pre- 
cipitated, and  titrate. 

The  amount  of  solution,  of  free  hydrochloric  acid  and  of  am- 
monium chloride  should  always  be  the  same  and  the  solution 
should  always  be  titrated  at  the  same  temperature,  which  should 
be  near  the  boiling  point. 

^  By  taking  care  to  complete  the  titration  by  adding  only  2  drops  of  ferrocyanide 
at  a  time,  a  delicate  end  reaction  may  be  obtained.  If  several  successive  spots  develop 
the  yellow  color  it  is  then  possible  to  deduct  from  the  burette  reading  the  value  of  the 
number  of  spots  added  after  the  end  color  was  first  obtained. 

2  Gelatinous  silica  combines  with  zinc  in  alkaline  solution. 

3  If  the  dry  mass  is  heated  much  above  the  boiling  point,  the  zinc  is  rendered 
difficultly  soluble  in  ammonium  chloride.  Furthermore  zinc  chloride  is  volatile,  in 
the  presence  of  hydrochloric  acid  at  a  comparatively  low  temperature. 

■*  It  is  very  difficult,  if  not  impossible,  to  wash  all  the  zinc  out  of  the  ferric 
hydroxide. 


ENGINEE^RING    CHE:mISTRY  95 

GRAPHIC  METHOD  FOR  CALCULATmG  BLAST-FURNACE 
CHARGES. 


The  rule  consists  o£  2  equal  scales  at  right  angles  (Fig.  15), 
one  of  which  (a)  is  fixed  to  a  small  board,  while  the  other  (b) 
is  fixed  at  right  angles  to  a  upon  a  block,  c,  which  is  capable  of 
sliding  motion  in  a  groove  parallel  to  a.^ 

The  point  A,  given  by  the  intersection  of  the  zeros  of  the 
scales,  is  marked  upon  the  board,  and  from  it  a  line  AB  parallel 
to  the  groove  is  drawn.  With  A  as  a  center,  lines  AC,  AD,  AE, 
are  also  drawn,  making  with  AB,  angles  whose  tangents  are 
equal  to  the  ratios  between  the  v/eight  of  the  silica  to  weight  of 
base  in  the  respective  silicates  which  it  is  desirable  to  produce 
in  order  to  form  the  typical  fusible  slags  ordinarily  met  within 
blast-furnace  practice. 

The  lines  AC,  AD,  AE,  are  marked  with  the  names  of  the 
bases  for  which  they  have  been  calculated. 

Thus  AC  makes  an  angle  of  28  degrees  10  minutes  with  AB — 
this  angle  having  a  tangent  whose  value  is  0.5357,  which  is  the 
ratio  of  the  atomic  weight  of  silica  to  twice  the  atomic  weight  of 
lime,  and  corresponds  to  calcium  silicate:  this  line,  therefore,  is 
marked  "Lime." 

Similarly  the  line  AD  makes  an  angle  of  36  degrees  52  minutes 
with  AB,  the  value  of  whose  tangent  is  0.75,  or  the  ratio  of  the 
atomic  weight  of  silica  to  the  atomic  weight  of  2MgO;  hence  it 
is  marked  "Magnesia." 

Also  the  line  AE  at  an  angle  of  41  degrees  25  minutes,  and 
this  having  a  tangent  corresponding  to  the  ratio  of  the  atomic 
weight  of  3Si02,  to  that  of  2AI2O3,  makes  the  line  correspond  to 
the  value  of  the  component  parts  of  silica  and  of  alumina  in 
aluminum  silicate,  and  so  it  is  marked  "Alumina." 

With  such  a  scale  it  is  a  very  simple  matter  to  at  once  read  off 
either  the  excess  of  silica  in  any  ore,  or  else  the  amount  required 
to  properly  flux  off  the  earthy  bases  present. 

^  H.   C.  Jenkins:     Iron  and  Steel  Institute,    1891. 


96 


ENGINEERING   CHEMISTRY 


, 

l- 

16 
15 
14 
13 
12 

11 

10 
9 
8 
7 
6 
5 
4 
3 
2 

0 

®  <l 

B 

I|II|I|ImI|III|||I|I|III||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||!|||||| 

lhiilllllllllllllllllllllllllililhlllllll!lllllllll!!l!l!!<l 

01^3456789 

12     13    14    15     16    17    18 

1 

)       c    1 

a 

Fig-    15. 

As  an  example,  take  a  spathic  ore  containing: 


silica  required. 
Per  cent. 


FeO  50  per  cent — 

MgO  3  per  cent 2.25 

CaO  5  per  cent 2.68 

AI2O3  3  per  cent 2.65 

SiOa  3  per  cent. — 

CO2  36  per  cent — 

Then  setting  the  movable  scale  h  against  3  on  the  fixed  scale 


Engine;e:ring  chemistry  97 

a  and  looking  along  b  until  the  line  marked  "Magnesia"  cuts 
it,  we  find  the  value  2.25  as  being  the  amount  of  silica  required 
to  satisfy  the  magnesia.  In  like  manner  is  found  the  amount 
(2.68)  of  silica  required  for  the  lime,  and  the  amount  (2.65)  for 
the  alumina  respectively;  adding  all  these  together  we  find  a 
total  of  7.58  parts  of  silica  required  for  every  100  of  the  ore. 

But  as  there  are  already  3  parts  present,  every  100  parts 
of  the  ore  require  7.58  —  3.0  =  4.58  parts  of  silica  added  to 
flux  it. 

Due  allowance  is  also  made  for  the  ash  of  the  coke,  and  any 
small  quantity  of  sulphur  in  the  mixture.  In  the  treatment  of 
several  kinds  of  ore  to  be  smelted  together  they  should  be  mixed 
and  divided  in  three  classes,  one  having  less  and  another  more 
iron  than  is  required  in  the  final  charge,  and  one  should  be  acid 
and  another  basic  after  the  correction  for  the  ash  of  the  coke  is 
made,  or  one  of  these  three  may  be  a  limestone  or  a  silicious  flux ; 
it  need  not  necessarily  contain  iron. 

Then  let  it  be  required  to  have  n  parts  of  iron  per  100  of 
the  charge,  and  let  a^  a^  a^  be  the  percentages  of  iron  in  the  ores, 
and  ^1,  b^,  b^  percentages  of  deficiency  (or  excess)  of  silica  in  the 
same,  and  x,  y,  z,  the  number  of  parts  required  of  the  component 
ores  per  100  of  the  charge. 

FeO  SiOo 


Z  (^3  ±  ^3). 


then 


(i)  jir  4- jj/  -f  ^r  =  100 

100 
(3)  xbi  —yb^  dr  zb^  -=  O. 

By  solving  these  simple  equations  there  is  obtained,  at  once, 
the  number  of  parts  of  each  component  required  to  satisfy  the 
conditions  of  the  charge. 

If  it  is  desired  to  produce  a  more  acid  or  a  more  basis  slag,  it 
only  requires  that  the  scale  b  be  replaced  by  one  having  a  length 
7 


98  ENGINEERING    CHEMISTRY 

of  one-half  (for  bisilicate  slag),  or  twice  (for  bibasic  slag)  that 
of  the  normal  scale. 

The  Blast-Furnace  as  a  Power  Plant.^ 

The  modern  blast-furnace  may  be  considered  as  a  giant  gas 
producer  which  differs  from  the  ordinary  producers  principally 
in  that  the  fuel  gasified  is  burdened  to  its  maximum  capacity  with 
iron  ore  and  flux.  In  the  blast  furnace  as  in  the  gas  producer  the 
first  and  most  vital  reaction  is  C  -|-  O  =  CO  in  which  i  pound 
of  carbon  unites  with  4/3  pound  of  oxygen  forming  7/3  pound 
of  carbon  monoxide. 

The  oxygen  in  both  cases  is  supplied  from  the  atmosphere 
under  suitable  pressure.  Since  every  pound  of  oxygen  is  associ- 
ated with  "/23  pound  of  nitrogen  ^/^  X  "/23  +  Vs  =  6.8 
pounds  of  gas  is  produced  for  every  pound  of  carbon  gasified  by 
this  reaction.  In  the  gas  producer  the  heat  generated  is  utilized 
in  decomposing  steam,  HoO  -^  C  =  CO  -f-  2H  by  which  the 
quantity  and  calorific  power  of  the  gas  produced  is  greatly  in- 
creased. 

To  attain  the  highest  economy,  gas  producers  must  be  run  at 
the  lowest  temperature  which  wall  insure  the  decomposition  of  all 
the  steam  introduced  with  the  blast.  All  earthly  impurities  con- 
tained in  the  fuel  are  therefore  invariably  discharged  in  the  form 
of  ashes  or  clinker  and  no  fluxing  material  is  required. 

In  the  blast-furnace,  on  the  contrary,  the  highest  possible  tem- 
perature must  be  maintained;  all  HgO  is  most  carefully  guarded 
against  entering.  The  heat  generated  by  the  reaction  O  -j~  C  = 
CO  is  utilized  in  reducing  the  ore  to  the  metallic  state  and  in 
melting  the  metal  to  a  liquid  hot  enough  to  flow  freely  from  the 
hearth  of  the  furnace.  The  earthy  impurities  of  both  fuel  and 
ore  must  be  gotten  rid  of  in  the  same  way;  fluxing  material 
must  therefore  be  added  to  the  burden  in  proportion  necessary 
to  produce  a  liquid  slag. 

For  our  present  purpose  it  is  not  necessary  to  follow  out  the 
manifold  and  interesting  reactions  which  constitute  the  process 
of  smelting,  except  in  so  far  as  is  necessary  to  determine  with 

1  E.  A.  Uehling,  M.  E. 


'  .  ENGINEERING    CHEMISTRY  99 

some  degree  of  accuracy  the  quantity  and  quality  of  gas  produced 
in  the  blast  furnace.  Gasification  of  the  solid  fuel  in  the  blast- 
furnace takes  place  in  three  distinct  ways.  First,  through  com- 
bustion by  the  oxygen  of  the  blast,  O  -|-  C  =:  CO.  Second, 
through  contact  with  the  incandescent  ore,  reducing  the  latter 
according  to  the  reactions  FcoOg  -)-  C  =:  2FeO  -|-  CO  and 
FeO  +  C  =  Fe  +  CO  or  Fe.Og  +  2C  =  2Fe  -f  CO,  +  CO 
etc.,  etc.  Third,  through  the  agency  of  CO2  either  previously 
formed  in  the  process  of  reduction  or  driven  off  from  the  car- 
bonates charged  as  ore  or  flux,  vis.,  CO2  +  C  =  2CO. 

In  the  United  States  about  2  per  cent,  of  the  fuel  consumed  in 
all  the  furnaces  is  charcoal  and  from  6  per  cent,  to  8  per  cent,  is 
anthracite  coal,  90  per  cent,  to  92  per  cent,  is  coke.  It  cannot 
therefore  involve  an  appreciable  error  if  we  base  our  calculations 
on  coke  as  the  fuel,  which  we  shall  do. 

The  quantity  of  gas  produced  by  all  the  blast  furnaces  of  the 
United  States  depends  on  the  total  quantity  of  fuel  they  consume, 
but  of  this  we  have  no  reliable  record.  We  have,  however,  very 
accurate  statistics  of  the  quantity  of  pig  iron  produced,  and  from 
practical  experience  we  shall  be  able  to  determine  very  closely  on 
the  average  consumption  of  coke  per  ton  or  iron  made.  The 
latter  varies  between  1,600  and  3,600  pounds  per  gross  ton  (2,240 
pounds)  or  iron,  and  it  depends  on,  first,  the  quality  of  the  coke. 
Chemically  impure  or  physically  inferior  coke  will  not  carry  a 
heavy  burden.  However,  a  well-burned  hard  coke  containing  an 
excess  of  earthy  impurities  is  superior  to  physically  weak  and 
frail  coke  though  of  good  chemical  analysis.  Second,  on  the 
•equipment  of  the  plant.  Third,  on  the  management  of  the  plant. 
Fourth,  on  the  nature  of  the  ore.  Fifth,  on  the  class  of  pig  iron 
produced.  The  lowest  fuel  consumption  can  only  be  attained 
where  all  the  conditions  are  most  favorable,  and  the  highest  is 
met  with  only  where  at  least  two  of  the  first  three  conditions  are 
most  unfavorable  for  all  the  conditions  are  bad. 

Based  on  the  following  analysis  of  coke  and  pig  iron  we  shall 
not  be  far  wrong  by  assuming  the  average  consumption  of  coke 


loo  Enginkering  chemistry  ■ 

per  gross  ton  (2,240  pounds)  of  pig  iron  at  present  produced  in 
the  United  States  to  be  2,000  pounds. 

Analysis  or  Coke. 

Per  cent. 

Fixed  carbon   85.00 

Volatile  combustible  matter 2.00 

Ash   (including  sulphur  and  phosphorus) 10.00 

Moisture   3.00 


100.00 


The  chemical  constituents  of  pig  iron  are  quite  variable  but 
the  following  composition  will  not  be  far  from  the  average  of  the 
iron  produced  in  the  United  States. 

Average  Anai^ysis  of  Pig  Iron. 

Per  cent. 

Iron  93.50 

Carbon    3.75 

Silicon    1.50 

Manganese   0.80 

Phosphorus   0.40 

Sulphur   0.05 


100.00 


Composition  of  Burden. 

With  the  exception  of  carbon  and  to  a  large  extent  also  sul- 
phur, all  the  constituents  of  pig  iron  are  contained  in  the  fuel  ore 
and  flux,  in  combination  with  oxygen  principally  in  accordance 
with  the  following  formula,  which  we  shall  take  as  the  basis  of 
our  calculation: 

Iron  from  FcgOg  containing  30  per  cent,  oxygen. 
Silicon  from  SiO^  containing  53  per  cent,  oxygen. 
Manganese  from  MngO^  containing  28  per  cent,  oxygen. 
Phosphorus  from  P2O5  containing  y2  per  cent,  oxygen. 
Sulphur  from  SO3  containing  60  per  cent,  oxygen. 

The  flux  required  to  form  a  liquid  slag  with  the  earthy  im- 
purities of  ore  and  fuel,  we  shall  assume  to  consist  of  carbonate 
of  lime  95  per  cent,  pure : 


ENGINEJERING   CHEMISTRY  lOI 

Composed  of  56  X  0.95  =  53.2  per  cent.  CaO 
and  44  X  0.95  =:  41.8  per  cent.  CO2 
plus  impurities        5.0  per  cent. 

loo.o  per  cent. 
Weight  of  Gas  per  Ton  of  Pig  Iron. 

The  total  weight  of  gas  produced  in  a  blast-furnace  per  ton 
of  pig  iron  is  obtained : 

First,  from  the  weight  of  fixed  carbon  gasified.  According  to 
the  analysis  of  the  coke  we  have  2,000  X  0.85  =:  1,700  pounds 
of  solid  carbon  charged  into  the  furnace  for  every  ton  of  iron 
produced.  Considerable  of  this  carbon,  the  amount  depending 
on  the  physical  structure  of  the  coke,  is  reduced  to  powder  by 
abrasion  in  the  process  of  handling  while  being  charged  into  the 
furnace  with  the  ore,  much  of  which  is  blown  out  with  the  gas 
and  wasted.  We  will  assume  this  loss  at  ^  per  cent. 
1,700  X  0.005  =  8.5  pounds. 

Pig  iron  contains  from  3.5  to  4  per  cent,  of  carbon;  taking  the 
average  at  3.75  we  have  2,240  X  0-0375  =  84  pounds  absorbed 
per  ton  of  pig  iron,  leaving  1,700  —  (8.5  +  84)  ■=  1,607.5 
pounds  to  be  gasified  by  oxidation  in  the  process  of  smelting. 

Second,  from  the  weight  of  oxygen  combined  with  the  metals 
and  metalloids  reduced  in  the  process  of  smelting  as  follows: 

Pounds 

From  the  iron  2,24oX  0.935  X  Vt  = 897.6 

From  the  manganese  2,240  X  0.008  X  ^Vi65  = 6.95+ 

From  the  silicon  2,240  -{-  0.015  X  V*  = 29.4 

From  the  phosphorus  2,240  X  0.0045  X  Vai  = 13.00 

From  the  sulphur  2,240  X  0.0005  X  V2  = i-68 

Total  weight  of  oxygen  from  the  ore  per  ton  of 

pig  iron  =   948.63+ 

Third,  the  weight  of  gaseous  constituents  of  the  flux.  The 
quantity  of  flux  required  per  ton  of  pig  iron  varies  with  the  quan- 
tity and  nature  of  the  gangue  carried  by  the  ore  smelted.  The 
greater  the  quantity  and  the  more  silicious  the  ore  the  larger  the 
weight  of  the  base  (limestone)  that  must  be  added  to  produce 
the  proper  composition  of  slag. 


I02  ENGINEERING    CHEMISTRY 

If  we  assume  1,200  pounds  per  ton  of  pig  iron  we  shall  not  be 
far  from  the  average.  And  hence  we  have  1,200  X  0.418 
=z  501.6  pounds  of  CO2  of  which  501.6  X  Vn  ^  364.8  pounds 
is  O  and  501.6  X  Vn  =  136.8  pounds  is  C. 

Fourth,  from  the  weight  of  air  delivered  into  the  blast-furnace 
by  the  blowing-engine. 

Fifth,  from  the  weight  of  the  volatile  combustible  contained  in 
the  coke. 

In  the  ideal  working  of  a  blast-furnace,  all  the  carbon  not 
absorbed  by  the  iron  should  descend  into  the  zone  of  the  com- 
bustion and  be  burned  to  CO  by  the  oxygen  of  the  blast.  The 
reaction  O  -|-  C  =  CO  should  produce  all  the  heat  required  in 
the  process  of  smelting  and  the  CO  gas  act  as  the  sole  reducing 
agent.  In  actual  practice,  however,  probably  not  over  80  per 
cent,  of  the  carbon  gasified  is  oxidized  by  the  blast  at  the  tuyeres. 
Deducting  the  amount  lost  and  absorbed  by  the  iron  we  have,  as 
found  above,  1,607.6  pounds  left  for  gasification,  80  per  cent,  of 
which,  vi:s.,  1,607.5  X  0.80  =  1,286  pounds  is  burned  at  the 
tuyeres  by  the  oxygen  of  the  blast.  Since  every  pound  of  C 
burned  to  CO  requires  1^3  pounds  of  O,  V3  X  1,286  -|-  1,714.67 
pounds  of  O  must  be  furnished  by  the  blast. 

Atmospheric  air  carries  a  variable  amount  of  moisture,  which 
runs  from  below,  o.oi  per  cent,  in  very  cold  winter  weather  to 
occasionally  over  2  per  cent,  in  summer.  This  moisture  plays  an 
important  part  in  the  heat  economy  of  the  blast-furnace^  and  to 


1  pound  of  C  oxidized  to  CO  develops  4,331  heat  units,  hence  5.746-33    ^  j^^  pounds  of 

4. 33' 

carbon  must  be  burned  in  the  hearth  of  the  furnace  to  counteract  the  chilling  effect  of 
I  pound  of  water  vapor  entering  with  the  blast. 

Taking  the  average  humidity  of  the  atmosphere  during  the  summer  months  at  1.5 
per  cent,  which  is  often  exceeded,  we  find  that  it  takes  7,247.47  X  0.015  =  10S.7  pounds  or 

108.7  X  100  ^  g^  cent,  of  the  carbon  consumed  at  the  tuyeres  to  take  care  of  the 

1,286 
moisture  of  the  blast  per  ton  of  iron.    Applying  these  figures  to  an  average  plant  of 
250,000  tons  annual  capacity  and  assuming  the  price  of  coke  at  I3.00  per  ton,  we  have  a 

loss  of  250.000  X  108.7  X  3-00  ^  $47,955-88  per  annum  which  shows  that  the  problem  of 

2,000  X  0.85 
desiccating  the  blast  is  one  of  sufficient  commercial  importance  to  make  it  worthy  of 
serious  investigation. 


ENGINEERING   CHEMISTRY 


103 


an  appreciable  extent  also  effects  the  quality  of  the  gas  for  the 
purposes  here  under  consideration.  The  average  moisture  car- 
ried by  the  blast  the  year  around  is  about  i  per  cent.,  and  where 
the  blowing-engines  draw  their  air  from  the  engine  house  leaky 
steam  joints  not  infrequently  double  the  average  quantity,  with 
very  unsatisfactory  results  as  to  fuel  economy. 

Water  is  composed  of  i  part  hydrogen  and  8  parts  oxygen,  and 
dry  air  is  a  mixture  of  23  parts  of  oxygen  and  "jy  parts  of  nitro- 
gen, hence  if  we  let  A  ^^  1,714.67,  i.  e.,  the  total  weight  of  O  re- 
quired to  burn  all  the  carbon  that  reaches  the  tuyeres  to  CO  and 

let  X  =  the  weight  of  O  furnished  by  the  dry  air  of  the 
blast 

and  3;  =  the  weight  of  moisture  (HgO)  carried  in  by  the 
blast,  which  we  have  assumed  to  be  i  per 
cent,  of  the  total  weight  of  the  latter. 


then  X 

9 

aiadjK  = 

-{x  +  71^ 

23 

+  r)  X 

O.OI. 

from  which  we  find 

X      = 

1,650.25  lbs 

0      from  dry  ai 

77-^  _ 
23 

5.524.75 

N 

t       <  i     ( ( 

together 

7,175.00  " 

( 

(       ( <     ( ( 

y 

72.47  " 

H,0 

moisture 

%y  = 

8.05  '' 

H     in 

( ( 

%y  = 

64.42  " 

0      •' 

{ ( 

A  =  1,650.25  +  64.42  =  1,714.67  pounds  =  total  weight  O 
required  per  ton  of  iron.  7,175  -f-  72.47  =  7,247.47  pounds  total 
weight  of  blast.  The  volatile  combustible  constituent  of  the  coke, 
the  CH4  =  40  pounds  which  together  with  the  moisture  of  coke 
ore  and  flux  passes  off  with  the  gas  unchanged.  The  moisture 
contained  in  the  gas  as  it  comes  from  the  furnace  is  a  very  variable 
quantity  and  does  not  require  special  consideration,  since  the  final 
per  cent.  H2O  contained  in  it  depends  entirely  on  the  temperature 


I04  ENGINEERING    CHEMISTRY 

at  which  the  gas  is  washed  and  purified.  In  the  following  cal- 
culations we  shall  assume  the  gas  saturated  w^ith  moisture  at 
82°  F. 

Up  to  date  but  little  is  done  in  the  way  of  properly  purifying 
the  blast-furnace  gas;  yet  it  is  as  irrational  and  uneconomical  to 
burn  this  gas  as  it  comes  from  the  furnace,  as  it  would  be  to  burn 
coal  mixed  with  all  the  slate  and  rock,  that  is  necessarily  brought 
to  the  surface  with  it  in  the  process  of  mining. 

Having  now  determined  the  weights  of  the  various  constitu- 
ents which  constitute  the  total  volume  of  gas  produced  per  ton 
of  pig  iron  it  remains  only  to  arrange  them  in  proper  order  and 
sum  them  up  as  follows : 

Pounds     Pounds 
First,  weight  of  solid  carbon  gasified : 

(a)  by  oxygen  from  the  blast 1,286.0 

(b)  by  oxygen  from  the  ore 321.5 

Second,  weight  of  carbon  derived  from  the 

burden    136.8 

Total  carbon   1,744-3 

Third,  weight  of  oxygen  derived  from  the 
burden : 

(a)  from  the  ore  948.63 

(b)  from  the  flux    364.80 

Fourth,  weight  of  oxygen  from  the  blast : 

(a)  from  the  dry  air 1,650.25 

(b)  from  the  moisture 64.42 

Total  oxygen    3,028.10 

Fifth,  weight  of  nitrogen  from  the  blast 5,524.75 

Sixth,  weight  of  hydrogen  from  the  blast 8.05 

Seventh,  weight  of  methane  from  the  coke 40.00 

Eighth,  weight  of  water  vapor 244.42 

Total  weight  of  gas  per  ton  of  pig  iron. .   10,589.62 

Calorific  Power  of  the  Gas. 

With  the  exception  of  the  small  amount  of  carbon  in  combi- 
nation with  hydrogen  as  CH^  (methane)  which  is  distilled  from 
the  coke  and  separately  accounted  for,  all  the  C  contained  in  the 
gas  is  combined  with  O,  first,  forming  CO  with  which  the  excess 


DNGINEERING   CHE:miSTRY  IO5 

of  O  unites  producing  COg.  To  enable  us  to  calculate  its  calo- 
rific power  it  is  necessary  to  know  the  respective  weights  of  CO 
and  COo  contained  in  the  gas. 

To  determine  the  weight  of  each  of  these  constituents  we  may- 
proceed  as  follows : 

I^et  A  =  total  weight  of  C  =  1,744.3  pounds. 

B  =  total  weight  of  O  =  3,028.10  pounds. 

C  —  C  +  O  =:  CO2  +  CO  =  4,772.4  pounds. 

X  =  weight  of  CO. 

•y  z=  weight  of  COg. 
then 

Vt^'  +  Vii:y  =  A. 

From  the  above  equations  we  get 
X  =  2,841.55  pounds  CO. 
y  =z  1,930.85  pounds  COg. 
Inserting  these  weights  of  CO  and  CO2  in  place  of  the  weights 
of  C  and  O  of  which  they  are  composed,  we  have  weight  of  con- 
stituents of  blast-furnace : 

Gas  produced  in  smelting 
I  ton  of  pig  iron 

Pounds  Per  cent,  by  weight 

N  =  5,52475  52.18 

CO  =  2,841.55  26.83 

CO2  =  1,930.85 18.23 

CH4  =       40.00  0.38 

H  =        8.05  0.08 

H2O  =     244.42  2.30 

10,589.62  100.00 

Taking  the  average  of  results  obtained  by  investigators  ac- 
cording to  Kent,  I  pound  of  CO  generates  4,331  B.  t.  u. ;  i  pound 
of  CH4  generates  20,975  B.  t.  u. ;  i  pound  of  H  generates  51,717 
B.  t.  u. 

Hence  we  have  for  blast-furnace,  gas  of  the  above  analysis: 
0.2683  X  4,331  +  0.0038  X  20,975  +  0.0008  X  51717  =  1,283.09 
B.  t.  u.  per  pound  of  gas.  And  since  10,589.62  pounds  of  gas 
are  produced  in  the  process  of  smelting  i  ton  of  pig  iron,  we  have 


106  EJNGINEERING    CHEMISTRY 

10,589.62  X   1,283.09  =   13,587,330  B.  t.  u.  available  from  the 
gas  of  every  ton  of  iron  made. 

Gas  Required  to  Heat  the  Blast  per  Ton  of  Pig  Iron. 

Except  in  a  few  small  furnaces  making  special  brands  of  iron, 
all  the  blast  is  heated  before  entering  the  furnace.  The  tempera- 
ture varies  between  700°  and  1,500°,  1,200°  F.  being  about  the 
average. 

We  have  determined  above  that  the  average  weight  of  blast  per 
ton  of  iron  is  7,247.47  pounds  containing  i  per  cent,  of  moisture ; 
hence,  7,175.00  pounds  of  dry  air  and  72.47  pounds  of  moisture. 

The  blast  becomes  considerably  heated  by  compression  in  the 
blowing-engine.  No  attempt  is  made  to  retain  this  heat  and  most 
of  it  is  dissipated  before  reaching  the  stoves.  Assuming  it  to 
enter  at  100  degrees  there  remain  1,000  degrees  to  be  imparted 
to  the  blast  in  passing  through  the  stoves. 

Since  the  specific  heat  of  air  and  water  vapor  are  respectively 
0.24  and  0.475  it  will  require,  (7,1 75  X  0.24  +  72.47  +  0.475)  X 
1,100  =  1,932,067;  heat  units  to  raise  the  temperature  of  the 
blast  per  ton  of  pig  iron  from  100  degrees  to  1,200  degrees. 

There  are  no  reliable  records  of  tests  having  been  made  to 
determine  the  efficiency  of  hot-blast  stoves,  and  little  or  nothing 
has  been  done  to  determine  the  proper  relation  between  heating 
surface  and  weight  or  cubic  content  of  the  brick  composing  the 
checkerwork^  yet  the  modern  fire-brick  stove  works  very  economi- 
cally so  far  as  gas  consumption  is  concerned.  If  operated  with 
fairly  clean  gas  and  efficient  burners,  50  per  cent,  excess  of  air 
should  suffice  to  secure  complete  combustion  and  the  chimney 
temperature  should,  on  an  average,  exceed  400°. 

Heat  Available  for  Heatings  the  Blast. 

The  products  of  combustion  from  burning  i  pound  of  gas  are 
as  follows : 

^  The  writer  is  of  the  opinion  that  the  heating  capacity  of  the  average  stove  can 
be  doubled  by  proper  purification  of  the  gas  and  a  more  rational  relation  of  heating 
surface  to  mass  of  brick  woik. 


DNGINEIERING   CHEMISTRY  IO7 

required  to  burn  the  CO 

7t  X  0.2683  =  0.1533  lb. 
producing  0.2683  +  0.15332  =  0.4216  lb.  CO2. 
required  to  burn  the  CH* 

4  X  0.0038  =  0.0152  lb. 
producing  0.00855  lb.  H2O  and  0.01045  lb.  CO2. 
O  required  to  burn  the  H 

8  X  0.0008  =  0.0064 
producing  0.0072  lb.  H2O. 
Nitrogen  accompanying  O 

(0.1533  +  0.0152  +  0.0064)  'V23  =  0.5855  lb. 
Theoretical  amount  of  air  required  to  burn 

I  lb.  of  gas  0.1749  +  0.5855 —  0.7604  lb. 

adding  50  per  cent,  excess  of  0.7604  X  ^Vioo  =  0.3802  lb. 

Total  air  for  combustion 1.1406  lbs. 

Summing  up  we  get : 

Nitrogen  in  gas  0.5218 

Nitrogen  in  air  for  combustion 0.5855 

Nitrogen  in  products  of  combustion 1. 1073  lbs. 

CO2  in  gas 0.1823 

CO2  from  combustion  of  CO 0.4216 

CO2  from  combustion  of  CHi 0.0105 

CO2  total  in  products  of  combustion o.6iz^4  lb. 

H2O  in  gas   0.0230 

H2O  from  combustion  of  CH 0.0086 

H2O  from  combustion  of  H 0.0072 

H2O  from  air  required  for  combustion...  0.0114 

H2O  total  in  products  of  combustion 0.0502  lb. 

Excess  of  air  50  per  cent 0.3802  lb. 

Total  weight  of  products  of  combustion...     2.1521  lbs. 
Assuming  the  air  and  gas  to  enter  the  combustion  chamber  at 
an    average    temperature    of    60°    and    the    products    of    com- 
bustion to  pass  off  at  460°  we  obtain  heat  carried  off  by  the 
products  of  combustion  from  i  pound  of  gas  as  follows  : 

By  CO2  0.6144  X  0.22  X  400 =    54.07  B.  t.  u. 

By  H2O  0.0502  X  0.48  X  400 =      9.64  B.  t.  u. 

By  N  -j-  excess  of  air  (1.1073  +  0.3802)   X 

0.24  X  400  =  142.80  B.  t.  u. 

Total   206.51  B.  t.  u. 


I08  KNGINDERING   CHE:mISTRY 

Deducting  this  from  the  heat  generated  by  i  pound  of  gas 
we  have  1,283.08  —  206.51  =r  1,076.57  heat  units  available  for 
heating  the  blast. 

We  found  above  that  to  heat  the  blast  required  for  i  ton  of 
iron  to  1,200°,  1,932,067  heat  units  will  be  absorbed.  Allowing 
5  per  cent,  for  leakage  and  radiation  it  will  take 

1,932,067       +        (1,932,067       X        0.05)  QQ  Q  AC. 

7 =  1,884.38    pounds    of  gas  to 

heat  the  blast  for  i  ton  of  pig  iron. 

Power  Available  from  Blast-Fumace  Gas. 

Although  the  application  of  blast-furnace  gas,  to  internal  com- 
bustion engines,  is  of  comparatively  recent  date,  its  practicability 
has  already  been  demonstrated  on  a  commercial  scale.  A  large 
number  of  such  engines,  varying  from  50  to  1,200  horse-power, 
the  majority  over  500  horse-power,  are  to-day  in  successful 
operation  in  Europe,  Germany  being  far  in  the  lead. 

From  a  large  number  of  tests  it  has  been  found  that  from  20 
to  30  per  cent,  of  the  heat  energy  contained  in  the  gas  can  be 
realized  in  effective  power.  We  have  found  that  i  pound  of 
blast-furnace  gas  generates  1,283  B.  t.  u.  Now  since  2,545  units 
are  equivalent  to  i  horse-power  and  taking  the  average  efficiency 
of  the  blast-furnace  gas  engine  at  25  per  cent,  we  find  that 

■■ 1^—^ =  7.97  pounds  of  gas  are  required  per  horse-power 

1,283X0.25  '    ^-^  ^  o  ^  r  r 

hour.    Deducting  from  the  total  weight  consumed  in  heating  the 
blast   and   dividing   by   the   weight   per   horse-power   hour   just 

1,0589.62  —  1,884.38  ^     , 

found  we  have =    1,097.76     horse-power 

7-93 

per  ton  of  iron  produced  per  hour. 

The  power  legitimately  required  to  operate  the  plant  should  be 
below  200  horse-power  per  ton  of  iron  per  hour;  but  since  labor 
saving  machines  are  continually  being  added,  to  be  on  the  safe 
side,  we  shall  allow  250  horse-power  for  blowing-engines,  pumps 
for  all  necessary  purposes  including  cooling  water  for  gas  en- 
gines, for  handling  the  raw  material  and  product  for  lighting  the 


ENGINEERING    CHEMISTRY  IO9 

plant,  etc.,  etc.,  there  still  remains  1,097.76  —  250  =  847.76 
horse-power  for  sale  or  available  for  other  useful  work  for  every 
ton  of  iron  produced  per  hour. 

The  average  rate  of  production  of  pig  iron  in  the  United  States 
for  the  past  3  months  was  1,493,691  tons  per  month,  49,790  tons 
per  day  and  2,078  tons  per  hour;  hence  if  the  wasteful  steam- 
power  plants  were  replaced  by  internal  combustion  engines  at  all 
the  furnaces  there  would  be  available  a  surplus  of  847.76  X 
2,078  •=  1,761,645  horse-power. 

The  importance  of  the  blast-furnace  as  a  source  of  power  as 
well  as  the  efficiency  of  the  gas  engine  as  a  prime  mover,  are 
perhaps  even  more  vividly  brought  out  by  the  following  fact, 
than  by  the  collossal  figures  of  available  power  shown  above :  If 
the  coke  consumed  per  ton  of  iron  was  burned  direct  under  steam 
boilers  and  the  steam  generated  all  used  to  produce  power  in 

2  000 

steam  engines,  an  efficiency  of ^ —  =  1.82  pounds  of  fuel 

1,097.76 

per  horse-power  hour  must  be  realized  in  order  to  produce  an 
equal  power  to  that  obtained  from  the  gas  engine  from  the  same 
weight  of  coke  charged  into  the  blast-furnace  even  after  de- 
ducting the  gas  required  to  heat  the  blast. 

When  we  consider  the  fact  that  it  is  quite  the  exception  that 
blast-furnace  plants  can  be  depended  on  for  any  surplus  power, 
that  on  the  contrary  in  the  majority  of  plants  thousands  of  tons 
of  coal  are  fired  under  the  boilers  to  assist  the  gas  in  producing 
the  necessary  steam  for  the  wasteful  blowing  engines  and 
pumps  in  a  still  more,  wasteful  boiler  plant,  and  compare  this 
with  the  actual  power  possibilities  of  the  blast-furnace  it  is 
somewhat  surprising  that  so  little  has  been  done  in  this  direction 
in  America. 

The  path  of  economy  does  not  lie  in  the  direction  compounding 
steam  cylinders,  or  increasing  the  heating  surface  of  the  steam 
boiler  plant.  Money  thus  spent,  unless  it  be  for  temporary  pur- 
poses is  more  or  less  wasted. 

A  modern  blast-furnace  plant  should  not  only  have  no  fuel 
expense    for   its    own   power   requirement,    but   should   have   a 


no  e;ngine:e:ring  chemistry 

surplus  of  power  of  at  least  800  horse-power  for  every  ton  pro- 
duced per  hour,  for  sale,  which  in  the  majority  of  localities  could 
be  made  the  source  of  a  handsome  revenue. 


STANDARD  METHODS  FOR  DETERMINING  THE  CONSTITUENTS 

OF  CAST  IRON,  AS  ADOPTED  BY  THE  AMERICAN 

FOUNDRYMEN'S  ASSOCIATION,  1908. 


Reported  by  the  Committee  of  the  American  Foundrymen's 
Association,  Philadelphia  Convention,  May  21-24,  1907. 

Committee. — J.  O.  Handy,  Pittsburgh  Testing  Laboratory;  W.  G.  Scott, 
J.  I.  Case  Threshing  Machine  Co. ;  H.  E.  Field,  Mcintosh  Hemphill  & 
Co. ;  R.  F.  FHnterman,  McCormick  Harvester  Co. ;  R.  S.  McPherran, 
AlHs  Chalmers  Co, ;  H.  C.  Loudenbeck,  Westinghouse  Air  Brake  Co. ; 
H.  E.  Diller,  Western  Electric  Co.,  Secy.  Met.  Section;  Booth-Garrett 
&  Blair,  Philadelphia,  Pa. ;  J.  R.  Harris,  Tenn.  Coal,  Iron  &  Ry.  Co. ; 
Henry  Souther,  Henry  Souther  Engineering  Co. ;  A.  P.  Ford,  Crane 
Company;  Dr.  Thos.  B.  Stillman,  Stevens  Institute  of  Technology. 

Determination  of  Silicon. 

Weigh  I  gram  of  sample,  add  30  cc.  nitric  acid  (1.13  specific 
gravity)  ;  then  5  cc.  sulphuric  acid  (cone.)  Evaporate  on  hot 
plate  until  fumes  are  driven  off.  Take  up  in  water  and  boil  until 
all  ferric  sulphate  is  dissolved.  Filter  on  an  ashless  filter,  with  or 
without  suction  pump,  using  a  cone.  Wash  once  with  hot  water, 
once  with  hydrochloric  acid,  and  three  or  four  times  with  hot 
water.  Ignite,  weigh,  and  evaporate  with  a  few  drops  of  sul- 
phuric acid  and  4  or  5  cc.  of  hydrofluoric  acid.  Ignite  slowly  and 
weigh.  Multiply  the  difference  in  weight  by  0.4702,  which  gives 
the  per  cent,  of  silicon. 

Determination  of  Sulphur. 

Dissolve  slowly  a  3-gram  sample  of  drilling  in  concentrated 
nitric  acid  in  a  platinum  dish  covered  with  an  inverted  watch 
glass.  x\fter  the  iron  is  completely  dissolved,  add  2  grams  of 
potassium  nitrate,  evaporate  to  dryness  and  ignite  over  an  al- 
cohol lamp  at  red  heat.     Add  50  cc.  of  a  i  per  cent,  solution 


ENGINEE^RING   CHEMISTRY  III 

of  sodium  carbonate,  boil  for  a  few  minutes,  filter,  using  a 
little  paper  pulp  in  the  filter  if  desired,  and  wash  with  a  hot 
I  per  cent,  sodium  carbonate  solution.  Acidify  the  filtrate 
with  hydrochloric  acid,  evaporate  to  dryness,  take  up  with  50 
cc.  of  water  and  2  cc.  of  concentrated  hydrochloric  acid,  filter, 
wash,  and  after  diluting  the  filtrate  to  about  100  cc,  boil  and 
precipitate  with  barium  chloride.  Filter,  wash  well  with  hot 
vvater  ignite  and  weigh  as  barium  sulphate,  which  contains 
13.733  per  cent,  of  sulphur. 

Determination  of  Phosphorus. 

Dissolve  2  grams  sample  in  50  cc.  nitric  acid  (specific  gravity 
1. 13),  add  10  cc.  hydrochloric  acid  and  evaporate  to  dryness.  In 
case  the  sample  contains  a  fairly  high  percentage  of  phosphorus  it 
is  better  to  use  half  the  above  quantities.  Bake  until  free  from 
acid,  redissolving  in  25  to  30  cc.  of  concentrated  hydrochloric 
acid;  dilute  to  about  60  cc,  filter  and  wash.  Evaporate  to  about 
25  cc,  add  20  cc.  concentrated  nitric  acid,  evaporate  until  a  film 
begins  to  form,  add  30  cc  of  nitric  acid  (specific  gravity  1.20) 
and  again  evaporate  until  a  film  begins  to  form.  Dilute  to  about 
150  cc.  with  hot  water  and  allow  it  to  cool.  When  the  solution  is 
between  70°  and  80°  C.  add  50  cc.  of  molybdate  solution.  Agitate 
the  solution  a  few  minutes,  then  filter  on  a  tarred  Gooch  crucible 
having  a  paper  disc  at  the  bottom.  Wash  three  times  with  a  3  per 
cent,  nitric  acid  solution  and  twice  with  alcohol.  Dry  at  100°  C. 
to  105°  C.  to  constant  weight.  The  weight  multiplied  by  0.0163 
equals  the  per  cent,  of  phosphorus  in  a  i-gram  sample. 

To  make  the  molybdate  solution  add  100  grams  molybdic  acid 
to  250  cc.  water,  and  to  this  add  150  cc  ammonia,  then  stir  until 
all  is  dissolved  and  add  65  cc.  nitric  acid  (1.42  specific  gravity). 
Make  another  solution  by  adding  400  cc.  concentrated  nitric  acid 
to  1,100  cc  water,  and  when  the  solutions  are  cool,  pour  the  first 
slowly  into  the  second  with  constant  stirring  and  add  a  couple  of 
drops  of  ammonium  phosphate. 

Determination  of  Manganese. 

Dissolve  I  ^/lo  grams  of  drillings  in  25  cc.  nitric  acid  (1.13 
specific  gravity),  filter  into  an  Erlenmeyer  flask  and  wash  with 


112  ENGINEERING   CHEMISTRY 

30  cc.  of  the  same  acid.  The  cool  and  add  about  ^  gram  of 
bismuthate  until  a  permanent  pink  color  forms.  Heat  until  the 
color  has  disappeared,  with  or  without  the  precipitation  of  man- 
ganese dioxide,  and  then  add  either  sulphurous  acid  or  a  solu- 
tion of  ferrous  sulphate  until  the  solution  is  clear.  Heat  until  all 
nitrous  oxide  fumes  have  been  driven  off,  cool  to  about  15°  C; 
add  an  excess  of  sodium  bismuthate^ — about  i  gram — and  agitate 
for  2  or  3  minutes.  Add  50  cc.  water  containing  30  cc.  nitric 
acid  to  the  liter,  filter  on  an  asbestos  filter  into  an  Erlenmeyer 
flask,  and  wash  with  50  to  100  cc.  of  the  nitric  acid  solution. 
Run  in  an  excess  of  ferrous  sulphate  and  titrate  back  with 
potassium  permanganate  solution  of  equal  strength.  Each  cc. 
of  N/io  ferrous  sulphate  used  is  equal  to  o.io  per  cent,  of 
manganese. 

Determination  of  Total  Carbon. 

This  determination  requires  considerable  apparatus ;  so  in  view 
of  putting  as  many  obstacles  out  of  the  way  of  its  general  adop- 
tion in  cases  of  dispute,  your  committee  has  left  optional  several 
points  which  were  felt  to  bring  no  chance  of  error  into  the 
method. 

The  train  shall  consist  of  a  pre-heating  furnace,  containing 
copper  oxide  (Option  No.  i)  followed  by  caustic  potash  (1.20 
specific  gravity),  then  calcium  chloride,  following  which  shall  be 
the  combustion  furnace  in  which  either  a  porcelain  or  platinum 
tube  may  be  used  (Option  No.  2).  The  tube  shall  contain  4 
or  5  inches  of  copper  oxide  between  plugs  of  platinum  gauze, 
the  plug  to  the  rear  of  the  tube  to  be  at  about  the  point  where 
the  tube  extends  from  the  furnace.  A  roll  of  silver  foil  about 
2  inches  long  shall  be  placed  in  the  tube  after  the  last  plug 
of  platinum  gauze.  The  train  after  the  combustion  tube  shall 
by  anhydrous  cupric  suphate,  anhydrous  cuprous  chloride,  cal- 

1  Formed  as  follows: — Heat  20  parts  of  caustic  soda  nearly  to  redness  in  an  iron 
or  nickel  crucible,  and  add  in  small  quantities  at  a  time,  10  parts  of  basic  bismuth 
nitrate,  previously  dried  in  a  water-oven.  Then  add  2  parts  of  sodium  peroxide  and 
pour  the  brownish  yellow  fused  mass  on  an  iron  plate  to  cool;  when  cold,  break  it  up 
in  a  mortar,  extract  with  water,  and  collect  on  an  asbestos  filter.  The  residue,  after 
being  washed  four  or  five  times  by  decantation,  is  dried  in  the  water-oven,  then  broken 
up  and  passed  through  a  fine  sieve — (Blair). 


ENGINEERING    CHEMISTRY  II3 

cium  chloride,  and  the  absorption  bulb  of  potassium  hydrate 
(specific  gravity  1.27)  with  prolong  filled  with  calcium  chloride. 
A  calcium  chloride  tube  attached  to  the  aspirator  bottle  shall  be 
connected  to  the  prolong. 

In  this  method  a  single  potash  bulb  shall  be  used.  A  second 
bulb  as  sometimes  used  for  a  counterpoise  being  more  liable  to 
introduce  error  than  correct  error  in  weight  of  the  bulb  in  use, 
due  to  change  of  temperature  or  moisture  in  the  atmosphere. 

The  operation  shall  be  as  follows :  To  i  gram  of  well-mixed 
drillings  add  100  cc.  of  potassium  copper  chloride  solution  and 
7.5  cc.  of  hydrochloric  acid  (concentrated).  As  soon  as  dissolved 
as  shown  by  the  disappearance  of  all  copper,  filter  on  previously 
washed  and  ignited  asbestos.  Wash  thoroughly  the  beaker  in 
which  the  solution  was  made  with  20  cc.  of  dilute  hydrochloric 
acid  (i  :  i)  pour  this  on  the  filter  and  wash  the  carbon  out  of 
the  beaker  by  means  of  a  wash  bottle  containing  dilute  hydro- 
chloric acid  (i  :  i)  and  then  wash  with  warm  water  out  of  the 
filter.    Dry  the  carbon  at  a  temperature  between  95  and  100°  C. 

Before  using  the  apparatus  a  blank  shall  be  run  and  if  the  bulb 
does  not  gain  in  weight  more  than  0.5  milligram,  put  the  dried 
filler  into  the  ignition  tube  and  heat  the  preheating  surface  and 
the  part  of  the  combustion  furnace  containing  the  copper  oxide. 
After  this  is  heated  start  the  aspiration  of  oxygen  or  air  at  the 
rate  of  three  bubbles  per  second,  to  show  in  the  potash  bulb. 
Continue  slowly  heating  the  combustion  tube  by  turning  on  tw*o 
burners  at  a  time,  and  continue-  the  combustion  for  30  minutes 
if  air  is  used;  20  minutes  if  oxygen  is  used.  (The  Shimer  cru- 
cible is  to  be  heated  with  a  blast  lamp  for  the  same  length  of  time.) 

When  the  ignition  is  finished  turn  off  the  gas  supply  gradually 
so  as  to  allow  the  combustion  tube  to  cool  off  slowly  and  then 
shut  off  the  oxygen  supply  and  aspirate  with  air  for  10  minutes. 
Detach  the  potash  bulb  and  prolong,  close  the  ends  with  rubber 
caps  and  allow  it  to  stand  for  5  minutes,  then  weigh.  The  in- 
crease in  weight  multiplied  by  0.27273  gives  the  percentage  of 
carbon. 

The  potassium   copper  chloride   shall  be  made  by  dissolving 


114  ENGINEERING   CHEMISTRY 

I  pound  of  salt  in  i  liter  of  water  and  filtering  through  an 
asbestos  filter. 

Option  No.  I. — While  a  preheater  is  greatly  to  be  desired,  as 
only  a  small  percentage  of  laboratories  at  present  use  them,  it 
was  decided  not  to  make  use  of  one  essential  to  this  method; 
subtraction  of  the  weight  of  the  blank  to  a  great  extent  eliminat- 
ing any  error  which  might  arise  from  not  using  a  preheater. 

Option  No.  2. — The  Shimer  and  similar  crucibles  are  largely 
used  as  combustion  furnaces  and  for  this  reason  it  was  decided 
to  make  optional  the  use  of  either  the  tube  furnace  or  one  of 
the  standard  crucibles.  In  case  the  crucible  is  used  it  shall  be 
followed  by  a  copper  tube  3/16  inch  inside  diameter  and  10 
inches  long,  with  its  ends  cooled  by  water  jackets.  In  the  center 
of  the  tube  shall  be  placed  a  disk  of  platinum  gauze,  and  for 
3  or  4  inches  in  the  side  towards  the  crucible  shall  be  silver  foil 
and  for  the  same  distance  on  the  other  side  shall  be  copper  oxide. 
The  ends  shall  be  plugged  with  glass  wool,  and  the  tube  heated 
with  a  fish  tail  burner  before  the  aspiration  of  air  is  started. 

Graphite. 

Dissolve  I -gram  sample  in  35  cc.  nitric  acid  (1.13  specific 
gravity)  filter  on  asbestos,  wash  with  hot  water,  then  with  potas- 
sium hydrate  (i.i  specific  gravity)  and  finally  with  hot  water. 
The  graphite  is  then  ignited  as  specified  in  the  determination  of 
total  carbon. 


PIG  IRON. 


"This  department  has  been  established  for  the  use  of  producers 
and  distributers  of  pig  iron.  It  is  not  intended  to  be  an  adver- 
tisement of  their  material,  but  to  impart  information  to  foun- 
drymen  who  are  often  unable  to  locate  the  brands  and  compo- 
sitions they  want.  Correspondence  and  the  free  use  of  this 
department  is  urged  upon  the  furnaces  and  selling  agents,  who 
may  thereby  gain  wider  fields,  and  at  the  same  time  place  the 
foundryman  in  a  position  to  select  from  a  larger  variety  of  irons 


ENGINEERING   CHEMISTRY 


115 


than  he  could  before. 
to  the  Secretary."^ 


Communications  should  be  sent  direct 


Silicou 


Sulphur 


Manganese 


Phosphorus 


Total 
carbon 


Rogers,  Brown,  Co. 

Victoria 

Buena  Vista 

Gem 

Alleghany 

Crane,  Topton,  Ma- 
cungie,  Allentown 

Henry  Clay 

Macungie  Mallea'e 
Crane  Low  Phos  •  • 

Oxford 

Greensboro 

Superior    Charcoal 

Iron  Co. 
Pioneer,  Marquette, 
Excelsior,  Champ. 
Antrim,    Elk  Rap- 
ids, Mich. 

Peninsula  

Crescent  

H.  R.  Durkee,  Chi. 

Ashland 

Briar  Hill 

Low  Moor 


1.50  to  5.00 
.61 

I. GO  to  3.00 

r.oo  to  2.75 

.75  to  3.50 
1.50104.50 

.75  to  1.50 
1,00  to  2.00 

.60  to  1. 00 

.75  to  5.00 


.019  to  .053 

.019 
.015  to  .06 
,03    to  .07 

,025  to  .06 
,03    to  .06 

.04 
.015 

oi    to  .05 
03    to  .06 


0,0    to  2. 90  trace  to. 018 


0.0  to  2. 
0.0  to  I. 
0.0    to  2.50 


50  trace  to.018 

to.015 

trace  to.015 


90  trace 


5  to  10.00 
1. 00  to  1.25 
2.00  to  7.00 


up  to  .05 
up  to  .05 


r.89  to  2.17 
1.65 
1.50 

1-25 

•75 
1. 00  to  1.30 

•75 

■  15 

.65  to  1. 00 

1. 00  to  1.30 


.30  to  .70 

.3010  .70 
.25  to  .40 
.25  to  .40 


.65  to  1. 00 
.60  to  1. 00 


•33 
•30 
.60 
.60 

.75 
2.50  to  4.00 

.15 
.025 

.65  to  .75 
•50  to  .75 


15  to  .22 


4.00 

2.85  to  3.55 
3.60  to  3.93 

3.15  to  3.70 

325 
4.20 

3^75 


.15  to 
.15  to 
.15  to 


up  to  .15 


FOUNDRY  CHEMISTRY.^ 

(a)  General  effect  of  impurities  on  ''Properties  of  Cast  Iron" 
and  "Structure  and  Composition  of  Cast  Iron" 

(b)  Carbon. 

Definitions. 

Annealing  or  Temper  Carbon. — This  is  an  amorphous,  finely 
divided  form  of  carbon  which  separates  from  white  iron  in  the 
soHd  condition  when  subjected  to  prolonged  heating  as  in  mal- 
leable iron. 

1  Transactions,  of  the  American  Foundrymen's  Association,  Dr.  Richard  Moldenke, 
Secty.,  VVatchung,  N.  J. 

2  Transactions,  of  the  American  Foundrymen's  Association,  Herbert  E.  Field.  1905. 


Il6  EJNGINKERING   CHEMISTRY 

Graphitic  Carbon. — This  is  a  form  of  carbon  which  separates 
from  cast  iron  while  the  iron  is  still  in  a  molten  condition  and 
while  it  is  still  solidifying.  It  generally  has  a  crystalline  ap- 
pearance. 

Crystalline. — A  substance  is  said  to  be  crystalline  when  it  is 
bounded  by  plain  surfaces  symmetrically  arranged. 

Amorphous. — A  substance  is  said  to  be  amorphous  when  its 
particles  have  no  regular  shape. 

Grain. — As  spoken  of  in  regai^d  to  cast  iron  this  means  a  com- 
bination of  crystalline  or  irregularly  shaped  particles  which  when 
joined  together  form  a  surface.  It  is  spoken  of  as  fine  grain, 
coarse  grain,  etc. 

Contraction. — When  used  in  connection  with  cast  iron,  this 
means  the  decrease  in  size  due  to  a  lowering  of  temperature. 

Shrinkage. — When  applied  to  cast  iron  this  term  is  generally 
confused  with  ''contraction."  It  is  used  to  describe  the  pulling 
or  drawing  away  from  the  liquid  or  plastic  portion  of  the  cast 
iron  due  to  the  contraction  of  some  part  of  the  casting  which  has 
already  solidified.  The  cavity  thus  left  is  called  in  foundry 
parlance,  a  'shrink.' 

Elements  Controlling  the  Properties  of  Cast  Iron 

Elements  Giving  Fluidity. — The  elements  or  impurities  which 
give  fluidity  to  cast  iron  are  carbon,  silicon  and  phosphorus. 

Elements  Giving  Low  Shrinkage. — The  elements  which  give 
low  shrinkage  to  cast  iron  are  carbon,  by  its  direct  action,  and 
silicon  and  phosphorus  by  their  action  on  the  carbon  or  by  their 
action  on  the  iron  and  through  it  on  the  carbon. 

Elements  Giving  Softness. — The  elements  which  give  softness 
to  cast  iron  are  graphitic  carbon,  by  its  direct  action  on  the  iron, 
silicon  by  its  action  in  forming  graphitic  carbon,  phosphorus  by 
its  action  in  keeping  the  iron  hot,  and  giving  more  time  for  the 
graphitic  carbon  to  separate  and  manganese  in  certain  instances 
by  neutralizing  the  hardening  effect  of  the  sulphur. 

Elements  Giving  Strength. — The  elements  which  give  strength 
to  cast  iron  are  combined  carbon,  up  to  certain  percentages,  by 


I 


DNGINKERING    CHEMISTRY  II7 

its  direct  action  on  the  iron,  manganese,  by  its  action  on  the 
carbon  and  sulphur,  and  sulphur  if  added  to  very  weak,  soft  iron. 

Elements  Necessary  to  Different  Divisions  of  Grey  Iron. 

Stove  Plate  Grades. — It  is  observed  that  fluidity  is  the  most 
desirable  property  for  stove  plate  grades,  and  that  softness  is 
next  in  importance.  From  what  has  just  been  observed  it  can 
readily  be  seen  that  stove  plate  and  like  grades  of  iron  must  be 
high  in  silicon  and  phosphorus,  as  these  will  give  fluidity  and 
softness. 

Light  Machinery  Grades. — For  the  light  machinery  grades 
while  fluidity  and  softness  are  very  desirable  properties,  they 
can  not  be  considered  to  the  exclusion  of  shrinkage  and  strength, 
for  these  latter  are  the  more  important  factors  in  these  grades. 
Hence  in  this  division  the  phosphorus  and  silicon  must  be  some- 
what lower  and  the  carbon  and  manganese  a  little  higher.  The 
former  to  reduce  the  shrinkage  and  the  latter  to  add  strength. 

Heavy  Machinery  Grades. — In  this  grade  fluidity  is  not  such 
an  important  feature  and  the  iron  on  account  of  the  cost  of 
machining  should  be  as  soft  as  possible  and  yet  be  strong  enough 
for  the  work  in  which  it  is  used.  I^ow  shrinkage  is  also  a  very 
important  item  in  heavy  machinery.  The  phosphorus  and  silicon 
must  be  decreased  and  the  carbon  and  manganese  increased  in 
order  to  keep  the  iron  soft  and  the  shrinkage  low. 

High  Strength  Grades. — In  this  grade  the  shrinkage  must  be 
taken  care  of  in  the  designing  and  the  casting  should  be  as  soft 
as  possible  and  still  be  sufficiently  strong  in  order  to  keep  down 
the  cost  of  machining,  which  is  apt  to  be  high  on  such  work.  In 
order  to  do  this  therefore,  the  manganese  is  increased  and  phos- 
phorus, silicon  and  carbon  decreased. 

Effect  of  Individual  Elements  on  Cast  Iron. 

CARBON. 

General  Effect  on  Cast  Iron. — The  element  carbon  forms  a 
very  important  part  of  cast  iron.  In  fact,  it  is  absolutely  neces- 
sary that  cast  iron  contain  carbon,  for  without  it  we  would  have 
a  substance  which  would  resemble  wrought  iron  with  its  high 


Il8  ENGINEERING   CHEMISTRY 

shrinkage,  lack  of  fluidity,  and  high  melting  point.  The  carbon 
mixed  with  the  iron  gives  it  that  property  which  makes  cast 
iron  so  valuable,  namely,  its  low  shrinkage.  It  reduces  its  melt- 
ing point  and  adds  to  its  softness  and  fluidity.  In  the  majority 
of  uses  to  which  cast  iron  is  put,  carbon  acts  as  the  medium 
through  which  the  other  elements  work. 

Percentage  of  Carbon  in  Cast  Iron. — The  percentage  of  car- 
bon in  cast  iron  varies  from  2  to  4^  per  cent.  The  average 
carbon  in  cast  iron  is  probably  about  3.40  per  cent.  The  per 
cent,  of  carbon  in  high  silicon  pig  iron,  with  silicon  8  to  10  per 
cent.,  runs  down  to  2  per  cent.,  while  some  castings  for  espe- 
cially strong,  heavy  work,  made  in  air  furnace,  also  have  a  very 
low  carbon.  Bessemer  iron,  on  the  other  hand,  often  runs  up  to 
4^  per  cent,  in  carbon,  as  do  some  charcoal  irons,  while  an 
occasional  coke  iron  runs  over  4  per  cent.,  but  the  majority  of 
such  run  between  3  and  4  per  cent.  Many  of  the  books  and 
papers  on  cast  iron  assert  that  the  variation  in  carbon  in  ordinary 
iron  is  not  sufficient  to  cause  any  difference  in  the  quality  of  the 
iron.  Such  is  not  the  case  however.  Other  elements  and  con- 
ditions being  the  same,  the  higher  the  total  carbon  in  the  iron,  the 
softer  will  the  castings  be.  An  increase  of  0.25  per  cent,  in  the 
total  carbon  exerts  a  notable  increase  in  the  softness  and  a  de- 
crease in  the  shrinkage  and  the  strength  of  the  iron. 

Condition  of  Carbon  in  Cast  Iron. — There  are  four  kinds  of 
carbon  in  cast  iron.  In  general  consideration,  however,  these  four 
are  included  under  two  divisions — graphitic  carbon  and  combined 
carbon.  Graphitic  carbon  may  be  divided  into  temper  carbon 
and  graphite,  while  combined  carbon  includes  carbide  carbon  and 
hardening  carbon.  Temper  carbon,  or  annealing  carbon,  is  the 
form  of  carbon  found  in  malleable  iron  after  annealing.  Graphite 
carbon  is  that  form  found  in  soft  cast  iron.  Carbide  carbon  is 
the  carbon  contained  in  a  true  compound  of  carbon  and  iron.  It 
occurs  to  a  greater  or  lesser  degree  in  all  cast  iron.  Chilled  iron, 
however,  contains  a  considerable  portion  of  its  carbon  in  this 
form.  Hardening  carbon  is  that  form  of  carbon  which  makes  the 
castings  hard.     All  cast  iron  contains  some  hardening  carbon. 


ENGINEERING   CHEMISTRY  II9 

The  harder  the  iron  the  greater  the  percentage  of  carbon  present. 
For  the  present  in  our  study,  we  will  confine  our  study  to  the  two 
divisions — graphitic  carbon,  and  combined  carbon. 

Graphitic  Carbon. 

Graphitic  carbon  exerts  a  softening  influence  on  cast  iron.  It 
reduces  shrinkage,  frequently  gives  to  the  iron  an  open  crys- 
talline appearance,  especially  in  large  sections,  and  decreases  the 
strength  if  present  in  the  crystalline  form  of  graphite. 

Combined  Carbon. 

Combined  carbon  hardens  cast  iron,  increases  the  shrinkage, 
gives  a  close  grain  to  the  iron,  lowers  the  melting  point,  and  in- 
creases the  strength  when  present  up  to  a  certain  percentage. 

ReivATion  of  Graphitic  to  Combined  Carbon. 

The  difference  in  the  grade  of  cast  iron  is  marked  by  the  in- 
crease or  decrease  in  the  proportion  of  the  combined  to  the 
graphitic  carbon.  The  so-called  very  soft  irons  contain  as  low 
as  0.1  of  I  per  cent,  of  combined  carbon,  while  the  other  3.40  or 
3.50  per  cent,  is  free  or  graphitic  carbon.  As  the  grades  grow 
harder  the  combined  carbon  increases,  and  ordinary  soft  iron 
contains  from  0.2  to  0.5  of  i  per  cent,  of  combined  carbon,  while 
the  harder  castings  run  up  to  0.6  of  i  per  cent.  Strong  iron  cast- 
ings generally  contain  0.45  to  0.9  per  cent,  of  combined  carbon. 
The  proportion  of  combined  carbon  continues  to  increase  as  we 
go  through  the  harder  grades  of  cast  iron  until  we  reach  the 
chilled  iron  grade.  In  the  chilled  part  all  of  the  carbon  is  in  the 
combined  condition. 

Factors  Controi^IvIng  the  Condition  of  Carbon. 

There  are  four  factors  which  determine  the  proportion  of  the 
combined  to  the  graphitic  carbon  in  cast  iron.  First,  the  total 
amount  of  carbon  present;  second,  thie  rate  at  which  the  iron 
cools ;  third,  the  temperature  of  the  iron  when  it  begins  to  cool ; 
fourth,  the  amount  and  kind  of  the  other  elements  present  in  the 
iron. 


i20  engineering  chemistry 

Condition  oe  Carbon  Controleed  by  Amount  of 
Carbon  Present. 

The  greater  amount  of  carbon  present  in  the  iron,  other 
elements  being  the  same,  the  greater  will  be  the  proportion  of 
the  graphitic  to  the  combined  carbon.  For  example,  an  iron  with 
4  per  cent,  total  carbon  would  have  a  greater  proportion  of 
graphite  than  an  iron  having  3  per  cent,  total  carbon  if  both  con- 
tained the  same  amount  of  other  elements,  were  cast  from  the 
same  temperature,  and  were  poured  into  the  same  sized  sections. 

Condition  oe  Carbon  Controeeed  by  Rate  oe  Cooeing. 

The  rate  at  which  an  iron  cools  has  a  very  important  influence 
upon  the  proportion  of  the  combined  to  the  graphitic  carbon. 
The  more  rapidly  an  iron  is  cooled,  the  greater  will  be  the  amount 
of  the  combined  carbon  present,  and  conversely,  the  slower  it  is 
cooled  the  greater  will  be  the  amount  of  graphitic  or  free  carbon 
present.  This  is  illustrated  very  clearly  in  chilled  iron  work. 
In  this  work,  the  part  next  to  the  chilling  surface  may  have  all 
its  carbon  in  the  combined  form,  while  the  part  away  from  the 
chilled  surface  may  have  but  a  small  proportion  of  its  carbon  in 
the  combined  condition.  For  example,  if  an  iron  containing  3 
per  cent,  of  carbon  be  cast  against  a  chill  and  the  mass  of  the 
metal  be  sufficient  to  allow  the  rest  of  the  iron  to  cool  slowly,  the 
part  next  to  the  chill  might  contain  3  per  cent,  of  combined  car- 
bon and  no  graphite,  while  the  part  away  from  the  chill  might 
contain  but  i  per  cent,  of  combined  carbon  and  the  other  2  per 
cent,  be  graphite.  The  part  next  to  the  chill  is  chilled  very  rap- 
idly ;  the  heat  being  taken  away  from  the  iron  so  quickly  that  the 
carbon  remains  in  the  combined  condition.  The  part  away  from 
the  chill  cools  more  slowly,  and  allows  more  time  for  the  carbon 
to  separate  as  graphite.  The  effect  of  sudden  cooling  upon  the 
carbon  may  be  clearly  shown  by  dropping  small  particles  of  mol- 
ten iron  into  water  and  casting  some  of  the  iron  out  of  the  same 
ladle  in  a  dry  sand  mould.  The  former  will  frequently  be  white 
and  hard  and  have  all  its  carbon  in  the  combined  condition,  while 
the  latter  will  be  grey  and  soft  and  have  nearly  all  of  its  carbon 


^ENGINEERING   CHEMISTRY  121 

in  the  graphitic  form.  If  a  cast  iron  roll  chilled  on  the  outside 
by  casting  it  in  a  heavy  iron  chill  be  broken  so  as  to  show  the 
round  section  of  the  roll,  and  then  a  series  of  holes  be  drilled  in 
a  straight  line  from  the  outside  to  the  center  and  the  chips  from 
each  one  of  these  holes  be  analyzed  separately,  we  would  find 
that  as  we  went  from  the  outside  to  the  center,  the  combined 
carbon  would  gradually  decrease  and  the  graphitic  carbon  would 
increase.  We  know  that  iron  sets  first  on  the  outside  of  the 
roll  and  that  the  center  of  the  roll  remains  hot  the  longest  and  as 
our  combined  carbon  was  greatest  on  the  outside,  we  have  an  il- 
lustration in  one  casting  proving  that  the  more  rapidly  the  iron 
is  cooled  the  greater  will  be  the  proportion  of  the  combined  to 
the  graphitic  carbon. 

Condition  of  Carbon  Controi,i,ed  by  the  Temperature. 

In  the  previous  paragraph  we  have  noted  that  the  slower  an 
iron  cools  the  greater  will  be  the  proportion  of  the  graphite.  It 
is  very  clear  then  that  the  higher  the  temperature  of  the  iron 
when  it  begins  to  cool,  the  greater  will  be  the  time  allowed  for 
the  cooling  and  hence  the  greater  the  proportion  of  the  graphite. 

Condition  oi^  the  Carbon  ControIvI^ed  by  Other  Impurities. 
The  kind  and  amount  of  other  impurities  present  effect  the 
condition  of  the  carbon  in  the  iron.  In  brief,  however,  silicon 
increases  the  graphite  and  decreases  the  combined  carbon.  The 
greater  the  amount  of  silicon  present  the  greater  will  be  the 
amount  of  graphite  until  all  the  carbon  is  in  the  free  form. 
Sulphur  increases  the  combined  carbon,  the  greater  the  amount 
of  sulphur  present,  the  greater  will  be  the  amount  of  the  com- 
bined carbon.  Manganese  in  its  direct  action  on  carbon  increases 
the  proportion  of  combined  carbon.  Phosphorus  probably  has 
no  direct  effect  upon  the  carbon,  other  than  that  it  prolongs  the 
cooling  of  the  iron  thus  giving  more  time  for  the  separation  of 
the  graphite,  and  thus  decreasing  the  combined  carbon. 

SILICON. 

General  Effect  on  Cast  Iron, — The  presence  of  carbon  is 
absolutely  necessary  to  cast  iron.      Silicon,  while  not  as  neces- 


122  ENGINEERING   CHEMISTRY 

sary  in  all  kinds  of  cast  iron  as  carbon,  is  quite  essential  to  all 
the  lighter  grades.  Its  value  lies  in  its  effect  on  the  carbon 
and  not  in  any  direct  effect  on  the  cast  iron.  Silicon  softens  iron, 
makes  it  fluid,  reduces  shrinkage  and  regulates  the  strength. 

Percentage  of  Silicon  in  Cast  Iron. — Silicon  is  found  in  pig 
iron  from  a  bare  trace  to  12  or  13  per  cent.  The  lowest  silicons 
found  in  pig  irons  in  every  day  use  are  in  the  lower  grades 
of  some  charcoal  irons.  A  few  furnaces  running  on  basic  iron 
occasionally  make  very  low  silicon  iron  as  do  the  Bessemer 
furnaces.  Irons  made  by  the  above  furnaces  occasionally  run 
down  to  0.15  of  a  per  cent,  silicon.  At  the  other  extreme  are  the 
so-called  high  silicon  irons  containing  about  10  per  cent,  silicon. 
Silvery  irons  running  from  4  to  6  per  cent,  make  up  the  next 
lower  grades.  The  so-called  soft  grades  of  the  southern  furnaces 
analyze  between  3  and  4  per  cent,  silicon  while  between  3  and  i 
per  cent,  come  from  the  various  grades  of  northern  and  southern 
iron  numbered  in  various  ways. 

Condition  of  Silicon  in  Cast  Iron. — The  condition  of  silicon  in 
cast  iron  has  not  been  determined  with  sufficient  completeness 
to  warrant  any  definite  statement.  It  probably  forms  a  definite 
compound  with  the  iron  although  some  believe  it  exists  as  free 
silicon  in  the  same  manner  as  carbon  exists  as  free  carbon.  This, 
however,  is  not  of  as  great  importance  as  is  the  condition  of 
carbon  in  cast  iron.  Carbon  acts  directly  on  the  iron;  silicon 
acts  through  the  carbon.  In  studying  carbon  we  must  ascertain 
the  effect  of  the  carbon  on  the  iron.  With  silicon  we  are  in- 
terested in  the  effect  of  the  silicon  on  the  carbon  rather  than 
the  individual  condition  of  the  silicon. 

Silicon  and  Its  Effect  of  the  Condition  of  Carbon. — Silicon 
causes  the  carbon  in  cast  iron  to  be  present  in  the  graphitic  state. 

The  presence  of  silicon  increases  the  tendency  for  the  carbon 
to  assume  the  graphitic  form.  The  more  silicon  there  is  present 
the  greater  the  proportion  of  carbon  which  will  be  found  in  the 
graphitic  state. 

It  is  upon  this  important  reaction  that  the  importance  of  sili- 
con in  cast  iron  depends.     Different  grades  and  qualities  of  cast 


e)nginee;ring  chemistry  123 

iron  require  different  proportions  of  combined  and  graphitic  car- 
bon. By  raising  or  lowering  the  siHcon,  the  correct  proportions 
of  carbon  can  be  readily  maintained. 

Effect  of  Silicon  Dependent  Upon  Amount  of  Carbon  Present. 
— No  effort  will  be  made  in  this  chapter  to  give  the  definite 
amounts  of  silicon  necessary  to  produce  different  proportions  of 
graphitic  and  combined  carbon.  The  general  causes  which  regu- 
late these  amounts  should  be  understood  however. 

Under  carbon  we  found  that  the  greater  the  amount  of  car- 
bon present  the  greater  will  be  the  proportion  of  graphitic  to 
combined  carbon.  With  this  in  mind  we  can  readily  under- 
stand that  it  will  take  less  silicon  to  produce  a  given  proportion 
of  graphitic  carbon  when  the  total  percentage  of  carbon  is  high 
than  when  the  total  percentage  of  carbon  is  low. 

The  Action  of  Silicon  in  Iron. — Silicon  is  valuable  in  cast  iron 
only  on  account  of  its  action  on  the  carbon.  If  carbon  were  not 
present,  silicon  would  make  iron  hard,  brittle  and  weak.  For 
this  reason  the  action  of  carbon  on  iron  must  be  constantly  kept 
in  mind  in  studying  silicon. 

Generai,  Effect  of  SiIvICon  on  Iron. 

Silicon  as  a  Softener. — Silicon  softens  iron  by  increasing  the 
amount  of  graphitic  carbon  in  the  iron  and  decreasing  the 
amount  of  combined  carbon  present.  Under  our  study  of  carbon 
we  noticed  that  the  more  combined  carbon  there  was  present  the 
harder  would  be  the  iron.  Silicon  by  increasing  the  graphitic  car- 
bon softens  the  iron. 

The  addition  of  silicon  to  iron  increases  the  softness  until 
practically  all  the  carbon  is  in  the  graphitic  state.  If  any  silicon, 
more  than  enough  to  produce  this  effect  is  added,  the  silicon 
will  harden  the  iron. 

Silicon  as  a  Regulator  of  Shrinkage. — We  noted  under  carbon 
that  graphitic  carbon  decreased  shrinkage.  Inasmuch  as  silicon 
increases  the  amount  of  carbon  in  the  graphitic  condition,  silicon 
becomes  a  remedy  for  shrinkage.  It  must  be  remembered  that 
it  is  the  graphitic  carbon  that  decreases  the  shrinkage.  If  the 
total  carbon  in  the  iron  is  too  low  to  produce  a  low  shrinkage 


124  Engine;ering  chemistry 

iron,  the  addition  of  any  amount  of  silicon  will  not  make  the 
iron  a  low  shrinkage  iron.  It  can  exert  an  effect  only  in  pro- 
portion to  the  amount  of  carbon  present. 

Silicon  as  a  Controller  of  Strength. — The  strength  of  cast  iron, 
other  elements  being  the  same,  depends  upon  the  proportion  of 
the  combined  to  the  graphitic  carbon.  Silicon  controls  this  ratio, 
and  consequently  controls  the  strength  of  cast  iron. 

Silicon  as  a  Controller  of  Fluidity. — The  change  of  carbon 
from  the  combined  to  the  graphitic  state  as  the  iron  cools  gives 
fluidity  to  the  iron.  Silicon  aids  this  change  and  consequently 
adds  to  the  fluidity  of  cast  iron. 


STANDARD  SPECIFICATIONS  FOR  BUYING  FOUNDRY 
PIGIRON.i 


It  is  recommended  that  foundry  pig  iron  be  bought  by  analysis,  and 
that  when  so  bought  these  Standard  Specifications  be  used. 

Percentages  and  Variations. 

In  order  that  there  may  be  uniformity  in  quotations,  the  following 
percentages    and   variations    shall   be   used. 

(These  specifications  do  not  advise  that  all  five  elements  be  specified 
in  all  contracts  for  pig  iron,  but  do  recommend  that  when  these  elements 
are  specified  that  the  following  percentages  be  used.) 


(Code) 


Silicon 

Sulphur 

(0.25  allowed  either  way) 

(Maximum) 

1.00  —  (La) 

(Code) 

0.04  —  (Sa) 

1.50  -  (Le) 

0.05  —  (Se) 

2.00  —  (Li) 

0.06  —   (Si) 

2.00  —  (Lo) 

0.07  —  (So) 

3.00  —  (Lu) 

o.g8  —  (Su) 
0.09  —  (Sy) 
0.10  —  (Sh) 

Total  carbon. 

(Minimum) 

300  — 

(Ca) 

( 

3-20  — 

(Ce) 

340  — 

(Ci) 

3.60- 

(Co) 

3.80- 

(Cu) 

Adopted  May  20th,   1909, 

(Code) 


ENGINEERING   CHEMISTRY  I25 

Manganese  Phosphorus 

(0.20  either  way)  (0.150  either  way) 

0.20  —  (Ma)         (Code)  0.20  —  (Pa)         (Code) 

0.40  —  (Me)  0.40  —  (Pe) 

0.60  —  (Mi)  0.60  —  (Pi) 

0.80  —  (Mo)  0.80  —  (Po) 

i.oo  —  (Mu)  i.oo  —  (Pu) 

1.25  —  (My)  1.25  —   (Py) 

1.50  —  (Mh)  1.50  —  (Ph) 

In  case  of  phosphorus  and  manganese,  the  percentages  may  be  as 
maximum  or  minimum  figures,  but  unless  so  specified  they  will  be  con- 
sidered to  include  the  variations  above  given. 

Base  Table. 

The  following  table  may  be  filled  out,  and  may  become  a  part  of  the 
contract:  "B"  or  Base,  represents  the  price  agreed  upon  for  a  pig  iron 
running  2.00  in  silicon  (with  allowed  variation  of  0.25  per  cent,  either 
way),  and  under  0.05  sulphur.  "C"  is  a  constant  differential  to  be  deter- 
mined at  the  time  the  contract  is  made.  (It  is  recommended  that  "C" 
be  25  cents  per  ton.) 

Silicon  percentages  allow  0.25  variation  either  way.  Sulphur  per- 
centages are  maximum. 


Sul- 
phur, 
per 

Silicon,  per 

cent. 

cent. 

3-25 

3.00 

2.75 

2.50 

2.25 

2.00 

1-75 

1.50 

1-25 

I.oo 

0.04  . 

.  B+6C 

B4-5C 

B+4C 

B+3C 

B+2C 

B  +  iC 

B 

B-iC 

B— 2C 

B-3C 

0.05  . 

.B+5C 

B+4C 

B+3C 

B+2C 

B  +  jC 

B 

B-iC 

B-2C 

B-3C 

B-4C 

0.06  . 

.B+4C 

B+3C 

B  +  2C 

B-f-iC 

B 

B-iC 

B— 2C 

B-3C 

B-4C 

B-5C 

0.07  . 

.  B+3C 

B+2C 

B-fiC 

B 

B— :C 

B— 2C 

B-3C 

B-4C 

B-5C 

B-6C 

o.oS  . 

.  B+2C 

B  +  iC 

B 

B— iC 

B— 2C 

B-3C 

B— 4C 

B-5C 

B-6C 

B-7C 

0.09  , 

.  B  +  iC 

B 

B— iC 

B— 2C 

B-3C 

B-4C 

B-5C 

B-6C 

B-7C 

B— 8C 

O.IO  . 

.  B 

B-iC 

B-2C 

B-3C 

B-4C 

B-5C 

B-6C 

B-7C 

B-8C 

B-9C 

Penalties- 

—In  case  the 

iron,  when  delivered. 

,  does 

not  conform 

to  the 

specifications,  the  buyer  shall  have  the  option  of  either  refusing  the  iron, 
or  accepting  it  on  the  basis  shown  in  the  above  table,  which  must  be 
filled  out  at  the  time  the  contract  is  made. 

Allowances. — In  the  case  the  furnace  cannot  for  any  good  reason 
deliver  the  iron  as  specified  at  the  time  of  delivery  is  due,  the  purchaser 
may  at  his  option  accept  any  other  analysis  which  the  furnace  can 
deliver.  The  price  is  to  be  determined  upon  by  the  table  above,  which 
must  be  filled  in  at  the  time  the  contract  is  made. 

Sampling  and  Analysis. 

Each    carload,    or   its    equivalent,    shall    be    considered    as    a   unit   in 
sampling. 

One  pig  of  machine-cast,  or  one-half  pig  of  sand  cast  iron  shall  be 


126  e;nginke;ring  chemistry 

taken  to  every  4  tons  in  the  car,  and  shall  be  selected  from  different 
parts  of  the  car.  Drillings  shall  be  taken  so  as  to  fairly  represent  the 
composition  of  the  pig  as  cast.  An  equal  weight  of  the  drillings  from 
each  pig  shall  be  thoroughly  mixed  to  make  up  the  sample  for  analysis. 
In  case  of  dispute,  the  sample  and  analysis  shall  be  made  by  an  inde- 
pendent chemist,  mutually  agreed  upon,  if  practicable,  at  the  time  the 
contract  is  made. 

It  is  recommended  that  the  standard  methods  of  the  American  Foun- 
drymen's  Association  be  used  for  analysis.  Gravimetric  methods  shall 
be  used  for  sulphur  analysis,  unless  otherwise  specified  in  the  contract. 
The   cost  of   resampling  and   reanalysis   shall  be  borne  by  the  party  in 


STANDAED  SPECIFICATIONS  FOR  METHODS  OF  CHEMICAL 

ANALYSIS  FOR  PLAIN  CARBON  STEEL.* 

Adopted,  1914. 


Determination  of  Carbon  by  the  Direct  Combustion  Method. 

The  method  of  direct  combustion  of  the  metal  in  oxygen  is 
recommended,  the  carbon  dioxide  obtained  being  absorbed  in 
barium  hydroxide  solution,  the  precipitated  barium  carbonate 
filtered  off,  washed,  dissolved  in  a  measured  excess  of  hydro- 
chloric acid  and  the  excess  titrated  against  standard  alkali. 

The  use  of  potassium  hydroxide  solution  or  soda  lime  for  the 
absorption  of  carbon  dioxide,  with  suitable  purifying  train  fol- 
lowing the  furnace,  is  recognized  as  being  capable  of  very  satis- 
factory refinement  and  as  possessing  merit  where  the  time  element 
is  of  prime  significance. 

Owing  to  the  diversity  of  apparatus  by  which  correct  results 
may  be  obtained  in  the  determination  of  carbon,  the  recommenda- 
tions are  intended  more  to  indicate  what  is  acceptable  than  to 
prescribe  definitely  what  shall  be  used. 

Apparatus. 
Purifying  Train. — The  method  employed  eliminates  the  neces- 
sity of  a  purifying  train  following  the  furnace,  inasmuch  as  no 
precautions  are  necessary  to  prevent  access  of  water  vapor,  or 
sulphur  trioxide — the  impurities  usually  guarded  against — from 

*  American   Society  for  Testing  Materials. 


e;ngine:e:ring  che^mistry  127 

the  absorbing  apparatus.  All  that  is  needed  is  a  calcium  chloride 
tower  filled  with  stick  sodium  hydroxide  placed  before  the  fur- 
nace, or  between  the  furnace  and  catalyzer,  if,  as  recommended, 
the  latter  is  used  for  the  purpose  of  oxidizing  organic  matter  in 
the  oxygen. 

Material  for  Lining  Boats. — Alundum,  "RR  Alundum,  alkali 
free,  specially  prepared  for  carbon  determination,"  as  supplied 
by  dealers  is  suitable,  and  is  recommended.  The  90-mesh  or 
finer  grades  are  used.  Chromite,  properly  sized  and  freed  from 
materials  causing  a  blank,  may  also  be  employed.  No  substance 
containing  alkali  or  alkaline  earth  metals,  or  carbon  as  carbonates 
or  in  other  form,  should  be  used  as  a  lining  material.  Quartz 
sand,  owing  to  its  liability  to  fuse  or  to  slag  with  the  oxides  of 
iron,  causing  bubbles  of  gas  to  be  enclosed,  is  objectionable. 
Aluminum  oxide,  made  by  calcining  alum  or  otherwise,  often 
contains,  sulphate  not  easily  destroyed,  or  may  contain  objection- 
able substances  of  an  alkaline  nature. 

Catalyzers. — Suitable  catalyzers  are  copper  oxide,  platinized 
quartz  or  asbestos,  or  platinum  gauze.  One  of  these  should  be 
used  in  the  forward  part  of  the  combustion  apparatus,  as  well 
as  in  the  purifying  train  preceding  the  combustion  tube  (see 
above).  Platinized  materials  sometime^  give  off  volatile  sub- 
stances on  heating,  and  whatever  material  is  used  should  not  be 
subject  to  this  defect. 

Combustion  Apparatus. — Any  apparatus  heated  by  gas  or  elec- 
tricity which  will  bring  the  sample  to  a  temperature  of  950°  to 
1,100°  C.  may  be  used.  Combustion  tubes  may  be  porcelain, 
glazed  on  one  or  both  sides,  quartz  or  platinum.  Quartz  is  liable 
to  devitrification  when  used  continuously  at  temperatures  above 
1,000°  C,  and  may  then  become  porous.  Combustion  crucibles 
of  platinum  may  be  heated  by  blast  or  by  Meker  burners. 

Boats  or  Other  Containers  of  Samples  Being  Burned. — These 
may  be  of  porcelain,  quartz,  alundum,  clay,  platinum,  or  nickel, 
and  should  always  receive  a  lining  of  granular  alundum. 

Purifying  Train  Before  Combustion  Apparatus. — This  consists 


128  DNGINEE^RING   CHEMISTRY 

of  a  tower  filled  with  stick  sodium  hydroxide,  preceded  by  a 
catalyzer. 

The  Train  After  the  Combustion  Apparatus. — This  consists 
merely  of  the  Meyer  tube  for  absorption  of  the  carbon  dioxide, 
protected  by  a  soda  lime  tube  at  the  far  end.  Meyer  tubes  with 
7  to  10  bulbs  of  10  to  15  cc.  capacity  each,  and  large  bulbs  at  the 
ends,  having  volumes  equal  to  the  combined  capacity  of  the  small 
bulbs,  have  been  used  and  found  satisfactory. 

Filtering  Apparatus. — In  filtration  for  accurate  work,  care 
should  be  taken  to  protect  the  solution  from  access  of  extraneous 
carbon  dioxide.  This  is  accomplished  in  the  apparatus  shown  in 
Fig.  16.  For  work  requiring  less  accuracy,  the  barium  carbonate 
may  be  filtered  off  on  a  filter  made  by  fitting  a  carbon  funnel 
with  a  perforated  porcelain  disk  and  filtering  by  suction.  The 
precipitate  is  then  washed  with  distilled  water  from  which  the 
carbon  dioxide  has  been  removed  by  boiling. 

Re:agents. 
Oxygen. — Oxygen  of  not  less  than  97  per  cent,  purity  is  recom- 
mended. Endeavor  should  be  made  to  obtain  oxygen  which  gives 
no  blank,  since  the  correction  for  or  elimination  of  this  is  trouble- 
some and  uncertain.  For  the  most  accurate  work,  particularly 
with  low  carbon  products,  such  as  ingot  iron,  etc.,  the  blank 
should  be  completely  eliminated  by  the  use  of  a  catalyzer  before 
the  furnace,  with  a  carbon  dioxide  absorbent  interposed  between 
furnace  and  catalyzer. 

Tenth-Normal  Hydrochloric  Acid. — This  may  be  standardized 
by  any  of  the  accepted  methods,  or  as  follows :  Twenty  cc.  of 
the  approximately  N/io  acid  is  measured  out  with  a  pipette,  and 
the  silver  chloride  precipitated  by  an  excess  of  silver  nitrate  soki- 
tion  in  a  volume  of  50  to  60  cc.  After  digesting  at  70  to  80°  C, 
until  the  supernatant  liquid  is  clear,  the  chloride  is  filtered  off  on 
a  tared  gooch  filter  and  washed  with  water  containing  2  cc.  of 
nitric  acid  per  100  cc.  of  water  until  freed  from  silver  nitrate. 
After  drying  to  constant  weight  at  130°  C,  the  increase  of  weight 
over  the  original  tare  is  noted  and  from  this  weight,  correspond- 
ing to  the  silver  chloride,  the  strength  of  the  hydrochloric  acid 


ENGINEERING   CHEMISTRY  I29 

is  calculated,  after  which  it  is  adjusted  to  the  strength  prescribed. 
The  standardization  should  be  based  upon  several  concordant 
determinations  using  varying  amounts  of  acid. 

I  cc.  N/io  HCl  =  0.0006  gram  carbon. 

Methyl  Orange. — Dissolve  0.02  gram  in  100  cc.  of  hot  distilled 
water  and  filter. 

Tenth-Normal  Sodium  Hydroxide  Solution. — This  is  stand- 
ardized against  the  hydrochloric  acid.  Methyl  orange  is  used 
as  the  indicator.  The  sodium  hydroxide  solution  should  be  stored 
in  a  large  bottle  from  which  it  may  be  driven  out  by  air  pressure, 
protecting  against  carbon  dioxide  by  soda  lime  tubes. 

Barium  Hydroxide  Solution. — A  saturated  solution  is  filtered 
and  stored  in  a  large  reservoir  from  which  it  is  delivered  by  air 
pressure,  protecting  from  carbon  dioxide  by  a  soda  lime  tube. 
Three  or  four  small  bulbs  of  the  Meyer  tube  are  filled,  and  CO2 
free  water  is  added  until  the  remaining  small  bulbs  are  filled. 

Factors  Infi^uencing  Rapid  Combustion. 

Si^e  of  Particles  of  Sample. — The  finer  the  chips  the  better, 
except  with  samples  which  burn  too  vigorously  (see  under  "Rate 
of  Admitting  Oxygen").  Particles  too  coarse  to  pass  a  20-mesh 
sieve  are  not  recommended,  nor  long  curly  drillings  which  will 
not  pack  closely.  A  ^-inch  flat  drill  may  be  used  for  taking  the 
sample  and  the  pressure  and  speed  of  the  drill  press  regulated 
to  secure  the  desired  result;  or,  better  still,  the  sample  may  be 
obtained  with  a  small  milling  machine  suitable  for  sampling,  or 
by  a  shaping  machine.  Oil,  dust,  and  other  foreign  matter 
should  be  carefully  excluded. 

Manner  of  Distributing  Sample  in  Boat. — This  is  of  consider- 
able importance.  With  all  samples,  close  packing  in  a  small 
space  is  conducive  to  rapid  comlpustion.  In  the  case  of  samples 
which  burn  too  vigorously,  a  satisfactory  regulation  may  some- 
times be  attained  by  spreading  the  sample  loosely  over  the  lining 
in  the  boat. 

Rate  of  Admitting  Oxygen. — The  rate  at  which  oxygen  is  ad- 
mitted is  also  a  factor  in  the  velocity  of  combustion.  Assuming 
9 


130  ENGINEERING   CHEMISTRY 

the  combustion  apparatus  {0  be  heated  to  the  temperature  range 
recommended  above  (950  to  1100°  C),  it  is  possible,  if  the 
material  is  closely  packed  and  if  oxygen  is  admitted  at  too  rapid 
a  rate,  that  the  combustion  may  be  so  violent  as  to  cause  excessive 
spattering  of  fused  oxides,  and  such  fluidity  of  the  molten  slag 
that  the  boat  or  other  container  may  be  injured  or  destroyed; 
therefore  a  moderate  rate  of  burning  is  to  be  sought.  This  is 
desirable  also  from  the  standpoint  of  the  complete  absorption 
of  the  carbon  dioxide  by  the  barium  hydroxide  solution.  The 
factors,  temperature  of  combustion  apparatus,  manner  of  dis- 
tribution of  sample,  and  rate  of  admission  of  oxygen,  can  be 
governed  so  as  to  burn  successfully  steels  of  a  very  wide  range 
of  compositions,  in  either  fine  or  coarse  particles. 

Method. 
After  having  properly  set  up  and  tested  the  apparatus,  place. 
2  grams  of  steel  (see  note  No.  i)  in  the  form  recommended 
above,  in  a  moderately  packed  condition  on  the  bed  material  and 
introduce  the  boat  into  the  combustion  apparatus,  already  heated 
to  the  proper  temperature.  After  about  a  minute  (to  allow  the 
sample  and  container  to  reach  the  temperature  of  the  furnace), 
admit  oxygen  somewhat  more  rapidly  than  it  is  consumed,  as 
shown  by  the  rate  of  bubbling  in  the  Meyer  tube  (see  note 
No.  2).  The  sample  burns  completely  in  i  or  2  mnutes,  and  all 
that  is  now  necessary  is  to  sweep  all  the  carbon  dioxide  into  the 
absorption  apparatus.  This  can  be  accomplished  in  6  to  8  min- 
utes by  passing  about  i  or  2  liters  of  oxygen.  Detach  the 
Meyer  tube  (see  note  No.  2)  and  filter  and  wash  the  barium 
carbonate,  using  the  sjpecial  filtering  apparatus  shown.  After 
solution  in  a  measured  excess  of  hydrochloric  acid  (the  Meyer 
tube  being  washed  out  with  a  portion  of  the  acid,  to  remove 
adhering  barium  carbonate),  titrate  the  excess  of  acid  against 
alkali  and  from  the  data  thus  obtained  calculate  the  percentage 
of  carbon. 

Notes. 
I.  When  working  with  steels  high  in  carbon   (above  i  per  cent.)  it  is 
advisable  not  to  use  more  than   i   gram  in  order  that  filtration  may  be 
sufficiently  rapid. 


ENGINEERING   CHEMISTRY 


131 


2.  As  a  precaution  against  error  resulting  from  too  rapid  passage  of 
the  gases,  it  is  well  to  attach  a  second  barium  hydroxide  tube  to  retain 
any  carbon  dioxide  that  may  pass  the  first. 

3.  For  the  most  accurate  work  the  Meyer  tubes  should  be  washed 
with  dilute  acid  before  beginning  work  each  day.  After  a  determination 
is  finished  the  tube  should  be  completely  filled  two  or  three  times  with 
tap  water,  then  rinsed  Math  distilled  water,  in  order  to  remove  the 
carbon  dioxide  liberated  when  dissolving  the  carbonate  from  the  previous 
determination. 

4.  The  flask  containing  the  carbonate  should  be  thoroughly  agitated 
after  adding  the  acid,  since  the  carbonate  sometimes  dissolves  rather 
slowly  if  this  is  not  done;  this  is  particularly  the  case  if  it  has  packed 
much  during  filtration. 

Apparatus  and  Procedure  for  Fii^tration. 
The  apparatus  is  shown  to  approximately  o.i  size  in  Fig.  15, 


Fig.    16. — Apparatus  for  filtration  in  determination  of  carbon  by  the 
direct  combustion  method. 


which  is  self  explanatory.  The  stop  cock  is  a  three-way  cock 
connected  to  the  suction  pipe.  The  rubber  tubing  connected  to 
the  Meyer  tube  should  be  of  best  grade  black  rubber,  and  the 
lengths  used  should  be  so  chosen  as  to  permit  of  easy  manipula- 
tion of  the  tube.  The  Meyer  tube  is  connected  or  disconnected 
by  the  rubber  stoppers  which  are  left  always  attached  to  the 


132  ENGINEERING   CHEMISTRY 

rubber  tubes.     The  carbon  tube  C  is  fitted  with  a  perforated 
porcelain  plate  sliding  easily. 

The  funnel  is  prepared  for  filtration  by  making  on  the  por- 
celain disk  a  felt  of  asbestos  about  ^/i(.  to  ^/^  inch  in  thickness, 
using  amphibole  (not  serpentine)  asbestos  which  has  been  care- 
fully digested  with  strong  hydrochloric  acid  for  several  hours 
and  washed  with  water  until  it  gives  no  acid  reaction.  On  top 
of  the  asbestos  pad  is  placed  a  layer  of  similarly  treated  quartz, 
mixed  with  asbestos,  of  the  height  shown.  A  mixture  of  quartz 
grains  of  various  sizes  (approximately  50  per  cent,  passing  a 
20-mesh  sieve  and  50  per  cent,  passing  a  lo-mesh  and  remaining 
on  a  20-mesh  sieve)  is  suitable.  The  mixture  of  quartz  and 
asbestos  may  be  obtained  by  filling  the  funnel  from  a  beaker 
(directing  against  it  a  stream  from  a  wash  bottle)  while  main- 
taining a  gentle  suction.  In  this  way  the  asbestos  is  properly 
mixed  with  the  quartz.  A  little  experience  and  attention  to 
these  details  will  enable  one  to  prepare  the  quartz  bed  in  a 
manner  that  will  greatly  expedite  filtration.  The  stopper  is  now 
inserted  in  the  funnel,  the  Meyer  tube  connected  as  shown  and 
the  liquid  and  precipitate  sucked  into  the  funnel.  Only  a  gentle 
suction  should  be  used.  When  necessary  P3  is  opened  to  admit 
air  back  of  the  column  of  liquid  in  the  Meyer  tube.  When  the 
contents  of  the  Meyer  tube  have  been  transferred,  the  large  bulb 
nearest  B  is  half  filled  with  water  opening  P^;  the  stop  cock 
S  is  operated  during  this  and  subsequent  operations  so  as  to 
maintain  a  gentle  suction  all  the  time.  M  is  now  manipulated  so 
as  to  bring  the  wash  water  in  contact  with  all  parts  of  the  interior, 
after  which  the  water  is  sucked  through  C ;  P2  is  left  open  during 
this  and  subsequent  washings.  After  eight  washings  as  directed, 
allowing  the  wash  water  to  drain  off  thoroughly  each  time  before 
adding  more,  M  may  be  detached,  the  stopper  removed  from  the 
funnel  and  the  washings  completed  by  filling  C  to  the  top  with 
CO2  free  water,  sucking  off  completely  and  repeating  the  opera- 
tion once.  With  care  the  washing  may  be  done  with  150  cc.  of 
water.  Air  is  now  admitted  through  the  side  opening  of  S,  C  is 
removed  and  the  porcelain  disk  carrying  the  asbestos,  quartz  and 


ENGINEERING   CHEMISTRY 


133 


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134  Engin^e;ring  chemistry 

barium  carbonate  is  thrust,  by  means  of  a  long  glass  rod,  into  a 
flask,  removing  any  adhering  particles  from  the  sides  of  C,  by  a 
stream  of  water  from  a  wash  bottle.  An  excess  of  the  standard 
acid  is  now  added  from  a  burette  or  pipette,  using  a  portion  to 
wash  out  M,  and  after  the  contents  of  the  flask  have  been  thor- 
oughly agitated  by  shaking,  the  excess  of  acid  is  titrated  against 
the  standard  alkali,  using  3  drops  of  the  methyl  orange  indicator. 

Notes. 

The  operation  of  filtering  can  be  carried  out  very  rapidly  after  a  little 
practice. 

Glass  wool  should  on  no  account  be  used  as  a  substitute  for  the 
quartz,  on  account  of  the  probability  of  errors  arising  from  its  attack  by 
the  alkali  or  acid. 

It  is  well  to  wash  out  the  rubber  tubes  connected  to  the  Meyer  tube 
with  a  little  water  each  day  before  beginning  work. 

Determination  of  Carbon  by  the  Colorimetric  Method^ 

This  method  depends  upon  the  color  given  to  nitric  acid 
(specific  gravity  1.2)  when  steel  is  dissolved  therein;  the  carbon 
present  producing  a  light-brown  or  dark-brown  coloration  to  the 
liquid  in  proportion  as  the  carbon  is  in  small  or  large  amounts. 
The  apparatus  (Fig.  18)  is  well  arranged  for  this  test.  It  con- 
sists of  a  series  of  graduated  tubes,  of  glass,  each  27.5  centimeters 
long,  15  millimeters  in  diameter,  and  graduated  to  hold  30  cc. 
divided  by  0.20  cc.  The  back  plate  of  the  apparatus  is  of  white 
porcelain,  25.5  centimeters  wide,  27  centimeters  high,  and  3  milli- 
meters thick,  and  I  found  it  much  better  than  the  various  cameras 
to  obtain  correct  comparisons  of  colors  of  solutions  in  the  differ- 
ent tubes.  Three  standard  steels  are  required,  one  containing 
I  per  cent,  combined  carbon,  for  tool  steels,  etc.,  one  containing 
0.4  per  cent,  carbon,  for  tires,  rails,  etc.,  and  0.2  per  cent.,  carbon, 
for  soft  steels,  these  percentages  of  carbon  having  been  very 
accurately  determined  by  combustion. 

The  process  is  as  follows :  Two-tenths  gram  of  the  standard 
steel  is  transferred  to  one  of  the  graduated  tubes,  and  0.2  gram 

^A.  I,add  Colby. 


ENGINDE^RING   CHEMISTRY  135 

of  the  steel  in  which  the  amount  of  carbon  is  to  be  determined  is 
transferred  to  another  graduated  tube  and  nitric  acid  (specific 
gravity  1.20)  added  and  the  tubes  placed  in  cold  water  to  pre- 
vent energetic  action  of  the  acid.  The  amount  of  nitric  acid  to 
be  used  is  as  follows :    steels  with  less  than  0.3  per  cent,  carbon. 


Fig.   18. 

3  cc.  acid;  0.3  to  0.5  per  cent,  carbon,  4  cc.  acid;  0.5  to  0.8  per 
cent,  carbon,  5  cc.  acid ;  and  so  on.^  After  a  few  minutes  interval 
the  tubes  are  placed  in  warm  water,  and  the  latter  gradually  raised 
to  the  boiling  point  and  maintained  at  that  temperature  about 
20  minutes  or  until  the  steel  dissolves. 

1  "Quantitative  Analysis   for  Mining  Engineers,"  by  Prof.   E.    H.   Miller,    1904. 


136  ENGINEERING   CHEMISTRY 

Suppose  the  standard  steel  contained  0.6  per  cent,  carbon,  the 
amount  of  nitric  acid  required  would  be  5  cc. 

After  solution  and  diluting  with  water  the  standard  to  8  cc.  it 
matches  the  solution  containing  the  other  steel  diluted  to  13  cc. 

The  amount  of  carbon  in  the  unknown  steel  would  be  0.977. 
Eight  cubic  centimeters  contains  0.6  per  cent.;  13  cc.  standard 
contains  0.97  per  cent. 

The  use  of  Eggertz'  color  test  for  combined  carbon  requires 
that  steels  should  have  been  subjected  to  a  similar  physical  treat- 
ment to  which  the  standard  steels  have  been  subjected  in  order 
to  secure  accurate  results.  A  steel  shows  less  carbon  by  color, 
when  hardened  than  when  unhardened,  and  less  unannealed  than 
when  annealed.  Several  modifications  of  the  process  have  been 
submitted  by  various  chemists,  but  they  offer  no  special  advan- 
tages. Stead  renders  the  nitric  acid  solution  of  the  steel  alkaline 
with  sodium  hydroxide,  which  dissolves  the  carbon,  producing  a 
solution  about  two  and  a  half  times  stronger  in  color  than  the 
solution  in  nitric  acid.  The  precipitated  iron  oxide  is  filtered  off, 
and  a  measured  quantity  of  the  colored  filtrate  is  transferred  to 
a  Stead  chromometer  and  the  color  compared  with  a  standard 
steel  under  similar  conditions ;  except  where  the  carbon  is  present 
in  minute  quantity  only  is  the  process  of  any  advantage  over  the 
Eggertz  method. 

Albert  I^add  Colby  states:  "Hardened  steel  should  be  thor- 
oughly annealed,  preferably  in  lime." 

The  standard  steel  used  in  this  case  should  have  been  annealed 
before  drillings  or  turnings  were  taken.  The  amount  of  nitric 
acid  used  in  dissolving  the  steel  should  vary  with  the  carbon 
present. 

The  following  table  showing  the  amount  of  acid  used,  the  per 
cent,  of  carbon  present  in  the  standard  steel  used  for  steels  of 
varying  carbon,  and  the  method  of  calculating  the  per  cent,  of 
carbon  in  the  sample,  is  the  result  of  a  long  experience  with  the 
Eggertz  method : 


^NGINEJERING   CHEMISTRY 


137 


Range 

No. 

Weight 
taken 
Grams 

Per  cent. 

Standard 

To  calculate  per  cent. 

in 

cc. 

carbon  in 

diluted  in 

carbon  in  steel  tested,  the 

per  cent. 

acid 

standard 

comparison 

reading  of  graduated 

carbon 

added 

steel 

tube  to 

tube  should  be 

1.20 — 0.80 

7 

0,02 

1.04    , 

20.8  CC. 

Divided  by  20 

0.79—0.60 

6 

0.02 

0.68 

13.6  CC. 

Divided  by  20 

0.59—0.50 

5 

0.02 

0.58 

II. 6  CC. 

Divided  by  20 

0.49 — 0.40 

5 

0.02 

0.49 

9.8  CC. 

Divided  by  20 

0.39-0.23 

4 

0.02 

0.34 

6.8  CC. 

Divided  by  20 

0.22—0.14 

4 

0.02 

0.201 

6.7  CC. 

Multiplied  by  0.03 

0.13— O.IO 

3 

0.02 

0. 114 

5.7  CC. 

Multiplied  by  0.02 

0.09 — 0.06 

3 

0.02 

0.082 

4.1   CC. 

Multiplied  by  0.02 

Special  apparatus  has  been  devised  which  greatly  facilitates  the 
application  of  the  Eggertz  method  to  the  rapid  determination  of 
carbon  in  consecutive  "blows"  of  Bessemer  steel.  The  sample  of 
each  *'blow"  should  be  sent  to  the  laboratory  in  the  form  of  a 
flat  bar  about  }i  inch  by  ^  inch  by  8  inches  long.  These 
bars  may  be  most  conveniently  obtained  by  passing  the  small  test 
ingot  through  a  set  of  small  rolls.  At  some  mills  the  test  ingot 
is  hammered  into  a  bar.  In  either  case  the  bar  should  be  allowed 
to  cool  slowly  on  refractory  bricks.  It  should  not  come  in  con- 
tact with  a  cold  metal  surface  during  cooling. 

The  solution  of  the  drillings  may  be  materially  hastened  by 
heating  in  a  calcium  chloride  bath,  kept  at  110°  C.  by  high  pres- 
sure steam,  instead  of  in  boiling  water;  and  when  dissolved  the 
solution  may  be  rapidly  cooled  by  transferring  the  test  tubes  to 
an  unglazed  earthenware  vessel  filled  with  water,  which  is  kept 
cold  by  evaporation  from  the  exterior  surface  of  the  vessel. 


Determination  of  Manganese  by  the  Bismuthate  Method. 

S01.UT10NS  Re:quire:d. 

Nitric  Acid. — Mix  500  cc.  of  nitric  acid  (specific  gravity  1.42) 
and  1,500  CC.  of  distilled  water. 

Nitric  Acid  for  Washing. — Mix  30  cc.  of  nitric  acid  (specific 
gravity  1.42)  and  970  cc.  of  distilled  water. 

Stock  Sodium  Arsenite. — To  15  grams  of  arsenious  acid 
(AS2O3)  in  a  300-cc.  Erlenmeyer  flask,  add  45  grams  of  sodium 
carbonate  and  150  cc.  of  distilled  water.    Heat  the  flask  and  con- 


138  ENGINEERING   CHEMISTRY 

tents  on  a  water  bath  until  the  arsenious  acid  is  dissolved,  cool 
the  solution  and  make  up  to  1,000  cc.  with  distilled  water. 

Standard  Sodium  Arsenite. — Dilute  300  cc.  of  stock  sodium 
arsenite  solution  to  1,000  cc.  with  distilled  water  and  titrate 
against  potassium  permanganate  solution  (about  N/io),  which 
has  been  standardized  by  using  Bureau  of  Standards  sodium 
oxalate.^  Adjust  the  solution  so  that  i  cc.  is  equivalent  to  o.io 
per  cent,  of  manganese,  when  a  i-gram  sample  is  taken. 

The  factor  NaaCjO^  »-^  Mn  =  0.16397  (using  the  1913  atomic 
weights). 

Method. 
In  a  300-cc.  Erlenmeyer  flask  dissolve  i  gram  of  steel  in  50  cc. 
of  the  nitric  acid,  and  boil  to  expel  the  oxides  of  nitrogen.  Cool, 
and  add  about  j^  gram  of  sodium  bismuthate  and  heat  for  a  few 
minutes,  or  until  the  pink  color  has  disappeared,  with  or  without 
precipitation  of  manganese  dioxide.  Add  small  portions  of 
ferrous  sulphate  (or  any  suitable  reducing  agent)  in  sufficient 
quantity  to  clear  the  solution,  and  boil  to  expel  the  oxides  of 
nitrogen.  Cool  to  15°  C,  add  an  excess  of  sodium  bismuthate 
and  agitate  for  a  few  minutes.  Add  50  cc.  of  3  per  cent,  nitric 
acid  and  filter  through  an  alundum  filter  or  asbestos  pad,  wash- 
ing with  3  per  cent,  nitric  acid.  Titrate  immediately  with  stand- 
ard sodium  arsenite  solution  to  the  disappearance  of  the  pink 
color,  each  cubic  centimeter  required  representing  o.io  per  cent, 
manganese. 

Notes. 

In  the  method,  the  preliminary  treatment  with  sodium  bismuthate  has 
been  found  by  a  number  of  investigators  to  be  apparently  unnecessary; 
however,  the  available  data  to  confirm  this  position  are  not  considered 
sufficient  to  warrant  its  omission. 

In  making  the  asbestos  filter  pad  it  is  advisable  to  have  a  thin  bed, 
and  as  much  surface  as  possible.  This  insures  rapid  filtration,  and  the 
filter,  may  be  used  until  it  becomes  clogged  with  bismuthate. 

The  filtrate  must  be  perfectly  clear,  since  the  least  particle  of  bis- 
muthate carried  through  the  filter  will  vitiate  the  results. 

^  Circular  No.  40,  Bureau  of  Standards,  Oct.  i,  19 12. 


ENGINEERING   CHEMISTRY  I39 

Determmation  of  Manganese  by  the  Persulphate  Method. 

(Routine.) 

S01.UT10NS  Required. 

Nitric  Acid. — Mix  1,000  cc.  of  nitric  acid,  specific  gravity  1.42,, 
and  1,200  cc.  of  distilled  water. 

Silver  Nitrate. — Dissolve  1.33  grams  of  silver  nitrate  in  1,000 
cc.  of  distilled  v^ater. 

Stock  Sodium  Arsenite. — To  15  grams  of  arsenious  acid 
(AS2O3)  in  a  300  cc.  Erlenmeyer  flask,  add  45  grams  of  sodium 
carbonate  and  150  cc.  of  distilled  water.  Heat  the  flask  and  con- 
tents on  a  water  bath  until  the  arsenious  acid  is  dissolved,  cool 
the  solution  and  make  up  to  1,000  cc.  with  distilled  water. 

Standard  Sodium  Arsenite. — Dilute  a  sufficient  quantity  of 
stock  sodium  arsenite  solution  with  distilled  water,  and  stand- 
ardize against  a  steel  of  known  manganese  content,  as  deter- 
mined by  the  bismuthate  method.  This  solution  should  be  of 
such  strength  that  each  cubic  centimeter  will  be  equivalent  to 
o.io  per  cent,  of  manganese  on  the  basis  of  the  weight  of  sample 
taken. 

Method. 

In  a  small  Erlenmeyer  flask  or  large  test  tube,  dissolve  o.i  to 
0.3  gram  of  steel,  depending  on  the  manganese  content  of  the 
sample,  in  15  cc.  of  the  nitric  acid.  Boil  gently  until  the  solution 
is  complete  and  the  liquid  is  clear.  Add  15  cc.  silver  nitrate  solu- 
tion and  I  gram  of  ammonium  persulphate,  and  continue  heating 
the  solution  for  y^  minute  after  the  oxidation  begins  and  bubbles 
rise  freely.  Cool  in  running  water  and  complete  the  determina- 
tion by  either  of  the  following  procedures  : 

(a)  C  olo  rime  trie . — Compare  the  color  of  the  solution  with  that 
of  a  standard  steel  treated  under  like  conditions. 

{h)  Titration. — Titrate  with  standard  sodium  arsenite  solution 
to  the  disappearance  of  the  pink  color,  each  cubic  centimeter 
required  representing  o.io  per  cent,  of  manganese. 

Notes. 
In  order  to  obtain  reliable  results  by  the  colorimetric  procedure,  the 
standard   should  be  of  the  same  kind  and  of   approximately  the  same 


I40  e;ngine;e)ring  chemistry 

chemical  composition  as  the  sample  steel.    The  manganese  content  of  the 
standard  steel  is  determined  by  the  bismuthate  method. 

The  ammonium  persulphate  should  be  kept  in  moistened  condition  by 
small  additions  of  distilled  water  at  required  intervals. 

Determination  of  Phosphorus  by  the  Molybdate  Magnesia  Method. 

Nitric  Acid. — Mix  i,ooo  cc.  of  nitric  acid,  specific  gravity 
1.42,  and  1,200  cc.  of  distilled  water. 

Nitric  Acid  for  Washing. — Mix  20  cc.  nitric  acid,  specific 
gravity  1.42,  and  1,000  cc.  of  distilled  water. 

Potassium  Permanganate. — Dissolve  25  grams  of  potassium 
permanganate  in  1,000  cc.  of  distilled  water. 

Ammonium  Bisulfite. — Dissolve  30  grams  of  ammonium  bisul- 
fite in  1,000  cc.  of  distilled  water. 

Ammonium  Hydroxide,  Approximately  10  Per  Cent. — Mix 
1,000  cc.  of  ammonium  hydroxide,  specific  gravity  0.90,  and 
2,000  cc.  of  distilled  water. 

Ammonium  Molybdate. 

Solution  No.  I. — Place  in  a  beaker  100  grams  of  85  per  cent, 
molybdic  acid,  mix  it  thoroughly  with  240  cc.  of  distilled  water, 
add  140  cc.  of  ammonium  hydroxide,  specific  gravity  0.90,  filter, 
and  add  60  cc.  of  nitric  acid,  specific  gravity  1.42. 

Solution  No.  2. — Mix  400  cc.  of  nitric  acid,  specific  gravity 
1.42,  and  960  cc.  of  distilled  water. 

When  the  solutions  are  cold,  add  solution  No.  i  to  solution 
No.  2,  stirring  constantly;  then  add  o.i  gram  of  ammonium  phos- 
phate dissolved  in  10  cc.  of  distilled  water,  and  let  stand  at  least 
24  hours  before  using. 

Magnesia  Mixture. — Dissolve  50  grams  of  magnesium  chloride 
and  125  grams  of  ammonium  chloride  in  750  cc.  of  distilled 
water,  and  then  add  150  cc.  of  ammonium  hydroxide,  specific 
gravity  0.90. 

Method. 
In  a  300  cc.  Erlenmeyer  flask  dissolve  5  grams  of  steel  in 
75  cc.  of  the  nitric  acid.    Heat  to  boiling;  while  boiling  add  about 
12   cc.   of   the  potassium  permanganate   solution,   and   continue 


e:ngine:e;ring  chemistry 


141 


boiling  until  manganese  dioxide  precipitates.  Dissolve  this  pre- 
cipitate by  additions  of  the  ammonium  bisulphite  solution,  boil 
until  clear  and  free  from  brown  fumes,  cool  to  35°  C,  add 
100  cc.  of  the  ammonium  molybdate  solution  at  room  tem- 
perature, let  stand  i  minute,  shake  or  agitate  for  3  minutes,^  filter 
on  a  9-centimeter  paper  and  wash  the  precipitate  at  least  three 
times  with  the  2  per  cent,  nitric  acid  solution  to  free  it  from  iron. 


Fig.    19. 


Treat  the  precipitate  on  the  filter  with  the  10  per  cent,  am- 
monium hydroxide  solution,  letting  the  solution  run  into  a  loo-cc. 
beaker  containing  10  cc.  of  hydrochloric  acid,  specific  gravity  1.20, 
and  0.5  gram  of  citric  acid;  add  30  cc.  of  ammonium  hydroxide, 
specific  gravity  0.90,  cool,  and  then  add  10  cc.  of  the  magnesia 
mixture  very  slowly,  while  stirring  the  solution  vigorously.  Set 
aside  in  a  cool  place  for  2  hours,  filter  and  wash  with  the  10  per 
cent,  ammonium  hydroxide  solution.  Ignite  and  weigh.  Dis- 
solve the  precipitate  of  magnesium  pyrophosphate  with  5  cc.  of 
nitric  acid,  specific  gravity  1.20,  and  20  cc.  of  distilled  water, 
filter  and  wash  with  hot  water.     Ignite  and  weigh.     The  differ- 

^  Use  of  Camp's  agitator  is  suggested  (Fig.    19). 


142  ^ngine;ering  chemistry 

ence  in  weights  represents  pure  magnesium  pyrophosphate  con- 
taining 27.84  per  cent,  of  phosphorus. 

Note. 
The  ^mmonium  molybdate  solution  should  be  kept  in  a  cool  place  and 
should  always  be  filtered  before  using. 

Determination  of  Phosphorus  by  the  Alkalimetric  Method. 

(Routine.) 

S0I.UTIONS  Require^d. 

Nitric  Acid. — Mix  1,000  cc.  of  nitric  acid,  specific  gravity  1.42, 
and  1,200  cc.  of  distilled  water. 

Nitric  Acid  for  Washing. — Mix  20  cc.  of  nitric  acid,  specific 
gravity  1.42,  and  1,000  cc.  of  distilled  water. 

Potassium  Permanganate. — Dissolve  25  grams  of  potassium 
permanganate  in  1,000  cc.  of  distilled  water. 

Ammonium  Bisulfite. — Dissolve  30  grams  of  ammonium  bisul- 
fite in  1,000  cc.  of  distilled  water. 

Ammonium  Molybdate. 

Solution  No.  i. — Place  in  a  beaker  100  grams  of  85  per  cent, 
molybdic  acid,  mix  it  thoroughly  with  240  cc.  of  distilled  water, 
add  140  cc.  of  ammonium  hydroxide,  specific  gravity  0.90,  filter 
and  add  60  cc.  of  nitric  acid,  specific  gravity  1.42. 

Solution  No.  2. — Mix  400  cc.  of  nitric  acid,  specific  gravity 
T.42,  and  960  cc.  of  distilled  water. 

When  the  solutions  are  cold,  add  solution  No.  i  to  solution 
No.  2,  stirring  constantly;  then  add  o.i  gram  of  ammonium  phos- 
phate dissolved  in  10  cc.  of  distilled  water  and  let  stand  at  least 
24  hours  before  using. 

Potassium  Nitrate,  i  Per  Cent. — Dissolve  10  grams  of  potas- 
sium nitrate  in  1,000  cc.  of  distilled  water. 

Phenol phthalein  Indicator. — Dissolve  0.2  gram  in  50  cc.  of 
,95  per  cent,  ethyl  alcohol  and  50  cc.  of  distilled  water. 

Standard  Sodium  Hydroxide. — ^Dissolve  6.5  grams  of  purified 
sodium  hydroxide  in  1,000  cc.  of  distilled  water,  add  a  slight 
excess  of  i  per  cent,  solution  of  barium  hydroxide,  let  stand  for 


ENGINEERING   CHEMISTRY  I43 

24  hours,  decant  the  liquid,  and  standardize  it  against  a  steel  of 
known  phosphorus  content,  as  determined  by  the  molybdate 
magnesia  method,  so  that  i  cc.  will  be  equivalent  to  o.oi  per 
cent,  of  phosphorus  on  the  basis  of  a  2-gram  sample  (see  notes). 
Protect  the  solution  from  carbon  dioxide  with  a  soda  lirfte  tube. 
Standard  Nitric  Acid. — Mix  lo  cc.  of  nitric  acid,  specific 
gravity  1.42,  and  1,000  cc.  of  distilled  water.  Titrate  the  solu- 
tion against  standardized  sodium  hydroxide,  using  phenol- 
phthalein  as  indicator,  and  make  it  equivalent  to  the  sodium 
hydroxide  by  adding  distilled  water. 

Method. 

In  a  300-cc.  Erlenmeyer  flask  dissolve  2  grams  of  steel  in  50 
cc.  of  the  nitric  acid.  Heat  the  solution  to  boiling  and  while  boil- 
ing add  about  6  cc.  of  the  potassium  permanganate  solution  and 
continue  boiling  until  manganese  dioxide  precipitate.  Dissolve 
this  precipitate  by  additions  of  the  ammonium  bisulfite  solution, 
boil  until  clear  and  free  from  brown  fumes,  cool  to  80°  C,  add 
50  cc.  of  the  ammonium  molybdate  solution  at  room  temperature, 
let  stand  i  minute,  shake  or  agitate  for  3  minutes,  and  filter  on  a 
9-centimeter  paper.  Wash  the  precipitate  three  times  with  the 
2  per  cent,  nitric  acid  solution  to  free  it  from  iron,  and  continue 
the  washing  with  the  i  per  cent,  potassium  nitrate  solution  until 
the  precipitate  and  flask  are  free  from  acid. 

Transfer  the  paper  and  precipitate  to  a  solution  flask,  add 
20  cc.  of  distilled  water,  5  drops  of  phenolphthalein  solution  as 
indicator,  and  an  excess  of  standard  sodium  hydroxide  solution. 
Insert  a  rubber  stopper  and  shake  vigorously  until  solution  of 
the  precipitate  is  complete.  Wash  oif  the  stopper  with  distilled 
water  and  determine  the  excess  of  sodium  hydroxide  solution  by 
titrating  with  standard  nitric  acid  solution.  Each  cubic  centi- 
meter of  standard  sodium  hydroxide  solution  represents  0.0 1 
per  cent,  of  phosphorus. 

Notes. 

The  ammonium  molybdate  solution  should  be  kept  in  a  cool  place 
and  should  always  be  filtered  before  using. 


144  ENGINEERING   CHEMISTRY 

All  distilled  water  used  in  titration  should  be  freed  from  carbon 
dioxide  by  boiling  or  otherwise. 

Bureau  of  Standards  Standard  Steel  No.  19  (a)  is  recommended  as  a 
suitable  steel  for  standardization  of  the  sodium  hydroxide  solution. 

Determination  of  Sulphur  by  the  Oxidation  Method. 

Solution  Required. 
Barium  Chloride. — Dissolve  100  grams  of  barium  chloride  in 
1,000  cc.  of  distilled  water. 

Method. 

In  a  400-CC.  beaker  dissolve  5  grams  of  the  steel  in  a  mixture 
of  40  cc.  of  nitric  acid,  specific  gravity  1.42,  and  5  cc.  of  hydro- 
chloric acid,  specific  gravity  1.20,  add  0.5  gram  of  sodium  car- 
bonate and  evaporate  the  solution  to  dryness.  Add  40  cc.  of 
hydrochloric  acid,  specific  gravity  1.20,  evaporate  to  dryness  and 
bake  at  a  moderate  heat.  After  solution  of  the  residue  in  30  cc. 
of  hydrochloric  acid,  specific  gravity  1.20,  and  evaporation  to 
sirupy  consistency,  add  2  to  4  cc.  of  hydrochloric  acid,  specific 
gravity  1.20,  and  then  30  to  40  cc.  of  hot  water.  Filter  and  wash 
with  cold  water,  the  final  volume  not  exceeding  100  cc.  To  the 
cold  filtrate  add  10  cc.  of  the  barium  chloride  solution.  Let  stand 
at  least  24  hours,  filter  on  a  9-centimeter  paper,  wash  the  pre- 
cipitate first  with  a  hot  solution  containing  10  cc.  of  hydrochloric 
acid,  specific  gravity  1.20,  and  i  gram  barium  chloride  to  the 
liter,  until  free  from  iron ;  and  then  with  hot  water  till  free  from 
chloride.     Ignite  and  weigh  as  barium  sulphate. 

Keep  the  washings  separate  from  the  main  filtrate  and  evap- 
orate them  to  recover  any  dissolved  barium  sulphate. 

Note. 

A  blank  determination  on  all  reagents  used  should  be  made  and  the 
results  corrected  accordingly. 

Determination  of  Sulphur  by  the  Evolution  Titration  Method. 

(Routine.) 
Apparatus. 
Use  a  480-CC.  flask  with  a  delivery  tube  and  a  300-cc.  tumbler 
of  tall  form  (Fig.  20). 


e;ngine:e:ring  chemistry 


145 


Capacity 
Iboz. 
=480cc 


Fig.   20. — Apparatus   for   determination   of  sulphur 
by  the  evolution  method. 


SoivUTlONS   RE)QUIRED. 

Dilute  Hydrochloric  Acid. — Mix  500  cc.  of  hydrochloric  acid, 
specific  gravity  1.20,  and  500  cc.  of  distilled  water. 

Ammoniacal  Cadmium  Chloride. — Dissolve  10  grams  of  cad- 
mium chloride  in  400  cc.  of  distilled  water  and  add  600  cc.  of 
ammonium  hydroxide,  specific  gravity  0.90. 

Potassium  lodate. — Dissolve  1.116  gram  of  potassium  iodate 
and  12  grams  of  potassium  iodide  in  1,000  cc.  of  distilled  water. 
Standardize  with  a  steel  of  known  sulphur  content.  Each  cubic 
centimeter  should  be  equivalent  to  o.oi  per  cent,  of  sulphur, 
when  a  5-gram  sample  is  used  (see  notes). 

Starch. — To   1,000  cc.  of  boiling  distilled  water,  add  a  cold 


146  ENGlNEEiRING    CHEMISTRY 

suspension  of  6  grams  of  starch  in  100  cc.  of  distilled  water; 
cool,  add  a  solution  of  6  grams  of  zinc  chloride  in  50  cc.  of  dis- 
tilled water,  and  mix  thoroughly. 

Me:thod. 

Place  5  grams  of  steel  in  the  flask  and  connect  the  latter  as 
shown  in  Fig.  17.  Place  10  cc.  of  the  ammoniacal  cadmium 
chloride  solution  and  150  cc.  of  distilled  water  in  the  tumbler.  Add 
80  cc.  of  the  dilute  hydrochloric  acid  to  the  flask  through  the 
thistle  tube,  heat  the  flask  with  its  contents  gently  until  the  solu- 
tion of  the  steel  is  complete,  then  boil  the  solution  for  ^  minute. 
Remove  the  tumbler  which  contains  all  the  sulphur  as  cadmium 
sulphide,  and  to  it  add  5  cc.  of  starch  solution  and  40  cc.  of  the 
dilute  hydrochloric  acid,  titrating  immediately  with  potassium 
iodate  solution  to  a  permanent  blue  color. 

Notes. 

Extremely  slow  or  rapid  evolution  of  hydrogen  sulphide  is  to  be 
avoided. 

Bureau  of  Standards  Standard  Steel  No.  8  (a)  is  recommended  for 
standardizing  the  potassium  iodate  solution. 

Determination  of  Silicon  by  the  Nitro  Sulphuric  Method. 

S01.UT10NS  Required. 

Nitro-Sulfuric  Acid. — Mix  1,000  cc.  of  sulphuric  acid,  specific 
gravity  1.84,  1,500  cc.  of  nitric  acid,  specific  gravity  1.42,  and 
5,500  cc.  of  distilled  water. 

Dilute  Hydrochloric  Acid. — Mix  100  cc.  of  hydrochloric  acid, 
specific  gravity  1.20,  and  900  cc.  of  distilled  water. 

METHOD. 

Add  cautiously  80  cc.  of  the  nitro  sulphuric  acid  to  4,702  grams 
of  steel,  in  a  platinum  or  porcelain  dish  of  300  cc.  capacity,  cover 
with  a  watch  glass,  heat  until  the  steel  is  dissolved  and  evaporate 
slowly  until  copious  fumes  of  sulphuric  acid  are  evolved.  Cool, 
add  125  cc.  of  distilled  water,  heat  with  frequent  stirring  until 
all  salts  are  dissolved,  add  5  cc.  of  hydrochloric  acid,  specific 
gravity  1.20,  heat  for  2  minutes,  and  filter  on  a  9-centimeter 
paper.    Wash  the  precipitate  several  times  with  hot  water,  then 


ENGINEERING   CHEMISTRY  I47 

with  hot  hydrochloric  acid  and  hot  water  alternately  to  complete 
the  removal  of  iron  salts,  and  finally  with  hot  water  until  free 
from  acid.  Transfer  the  filter  to  a  platinum  crucible,  burn  off 
the  paper  carefully  with  the  crucible  covered,  finally  igniting  over 
a  blast  lamp  or  in  a  muffle  furnace  at  i,ooo°  C.  for  at  least  20 
minutes ;  cool  in  a  desiccator  and  weigh.  Add  sufficient  sulphuric 
acid,  specific  gravity  1.84,  to  moisten  the  silica  and  then  a  small 
amount  of  hydrofluoric  acid.  Evaporate  to  dryness,  ignite  and 
weigh.  The  difference  in  weights  in  milligrams  divided  by  100 
equals  the  percentage  of  silicon. 

Note. 
A  blank  determination  on  all  reagents  used  should  be  made  and  the 
results  corrected  accordingly. 

Determination  of  Silicon  by  the  Sulphuric  Acid  Method. 

(Optional.) 
S01.UT10N  Required. 
Dilute  Hydrochloric  Acid. — Mix  100  cc.  of  hydrochloric  acid, 
specific  gravity  1.20,  and  900  cc.  of  distilled  water. 

Method. 

To  2,351  grams  of  steel,  in  a  beaker  of  low  form  of  500  cc. 
capacity,  add  60  cc.  of  distilled  water,  and  then  cautiously  15  cc. 
of  sulphuric  acid,  specific  gravity  1.84.  Cover  with  a  watch 
glass,  heat  until  the  steel  is  dissolved  and  evaporate  until  copious 
fumes  of  sulphuric  acid  are  evolved.  Cool,  add  100  cc.  of  dis- 
tilled water  and  heat  with  frequent  stirring  until  the  salts  are  in 
solution.  Filter  on  a  9-centimeter  paper,  wash  the  precipitate 
several  times  with  cold  water,  then  with  cold  dilute  hydrochloric 
acid  until  free  from  iron,  and  finally  with  cold  water  until  free 
from  acid.  Ignite  and  weigh.  Add  sufficient  sulphuric  acid, 
specific  gravity  i  .84,  to  moisten  the  silica  and  then  a  small  amount 
of  hydrofluoric  acid.  Evaporate  to  dryness,  ignite  and  weigh. 
The  difference  in  weights  in  milligrams  divided  by  50  equals  the 
percentage  of  silicon. 

Note. 

A  blank  determination  on  all  reagents  used  should  be  made  and  the 
results  corrected  accordingly. 


148  ENGINEERING   CHEMISTRY 

Determination  of  Copper. 

S01.UT10NS  Required. 

Sulphuric  Acid. — Mix  200  cc.  of  sulphuric  acid,  specific  grav- 
ity 1.84,  and  800  cc.  of  distilled  water. 

Potassium  Perrocyanide. — Dissolve  10  grams  of  potassium 
ferrocyanide  in  100  cc.  of  distilled  water. 

Standard  Copper  Nitrate. — Dissolve  2  grams  of  purest  electro- 
lytic copper  in  20  cc.  of  nitric  acid  (i  :  i),  and  dilute  to  1,000  cc. 
with  distilled  water.  Each  cubic  centimeter  is  equivalent  to 
0.02  per  cent,  of  copper  on  the  basis  of  a  lo-gram  sample. 

Method. 
In  a  300-cc.  beaker  dissolve  10  grams  of  the  steel  in  75  cc.  of 
the  sulphuric  acid,  and  then  add  150  cc.  of  distilled  water.  Heat 
the  solution  and  saturate  with  hydrogen  sulphide,  filter  and 
wash  the  precipitate  free  from  iron  with  i  per  cent,  sulphuric 
acid  containing  hydrogen  sulphide.  Incinerate  the  paper  with  its 
contents  in  a  porcelain  crucible  and  fuse  with  0.5  gram  of  acid 
sodium  sulphate.  Extract  with  hot  water,  filter,  and  complete 
the  determination  colorimetrically  as  under  i  (a)  or  i  {h) ,  or 
electrolytically  as  under  2,  as  follows : 

1.  Evaporate  the  filtrate  to  about  25  cc,  make  faintly  am- 
moniacal,  filter  into  a  loo-cc.  Nessler  tube  and  wash  with  hot 
water. 

{a)  If  the  solution  is  a  strong  blue,  to  another  100  cc.  Nessler 
tube  add  50  cc.  of  distilled  water,  5  cc.  of  ammonium  hydroxide, 
specific  gravity  0.90,  and  from  a  burette  the  standard  copper- 
nitrate  solution  until  the  blue  colors  match. 

{h)  If  the  solution  is  a  faint  blue,  to  the  filtrate  in  a  Nessler 
tube  add  the  dilute  sulphuric  acid  to  faint  acidity  and  then  a  few 
drops  of  the  potassium  ferrocyanide  solution.  To  another  loo-cc. 
Nessler  tube  add  50  cc.  of  distilled  water,  a  few  drops  of  the 
potassium  ferrocyanide  solution,  and  from  a  burette  the  standard 
copper  nitrate  solution  until  the  reddish  brown  colors  match. 

2.  Make  the  filtrate  slightly  acid  with  sulphuric  acid,  dilute 
with  distilled  water  to  a  suitable  volume,  and  determine  the 
copper  electrolytically. 


ENGINEERING   CHEMISTRY  I49 

Determination  of  Nickel  by  the  Gravimetric 
Dimethylglyoxime  Method. 

Solutions  Required. 

Hydrochloric  Acid. — Mix  500  cc.  of  hydrochloric  acid,  specific 
gravity  1.20,  and  500  cc.  of  distilled  water. 

Dimethylglyoxime. — Dissolve  i  gram  of  dimethylglyoxime  in 
100  cc.  of  95  per  cent,  ethyl  alcohol. 

Method. 
In  a  150-cc.  beaker  dissolve  i  gram  of  the  steel  in  20  cc.  of  the 
hydrochloric  acid,  and  add  about  2  cc.  of  nitric  acid,  specific 
gravity  1.42,  to  oxidize  the  iron.  Filter  the  solution  and  add  to 
the  filtrate  6  grams  of  tartaric  acid,  and  water  till  the  volume  is 
300  cc.  Make  the  solution  faintly  ammoniacal,  then  faintly  acid 
with  the  hydrochloric  acid  and  heat  nearly  to  boiling;  add  20  cc. 
of  the  dimethylglyoxime  solution  and  then  ammonium  hydroxide, 
specific  gravity  0.90,  drop  by  drop  till  faintly  alkaline,  stirring 
vigorously.  After  standing  i  hour,  filter  on  a  weighed  gooch 
crucible,  wash  with  hot  water,  dry  at  no  to  120°  C.  and  weigh. 
The  precipitate  contains  20.31  per  cent,  of  nickel. 

Notes. 

In  making  dimethylglyoxime  solution,  methyl  alcohol  may  be  substi- 
tuted for  ethyl  alcohol. 

The  weight  of  sample  taken  should  be  varied  according  to  the  nickel 
content. 

Determination  of  Nickel  by  the  Volumetric 
Dimethylglyoxime  Method. 

{Routine.) 
S01.UT10NS  Required. 
Hydrochloric  Acid. — Mix  500  cc.  of  hydrochloric  acid,  specific 
gravity  1.20,  and  500  cc.  of  distilled  water. 

Dimethylglyoxime . — Dissolve  i  gram  of  dimethylglyoxime  in 
100  cc.  of  95  per  cent,  ethyl  alcohol. 

Silver  Nitrate. — Dissolve  0.5  gram  of  silver  nitrate  in  1,000 
cc.  of  distilled  water. 


150  ENGINEERING   CHEMISTRY 

Potassium  Iodide. — Dissolve  20  grams  of  potassium  iodide  in 
100  cc.  of  distilled  water. 

Standard  Potassium  Cyanide. — Dissolve  2.29  grams  of  potas- 
sium cyanide  in  1,000  cc.  of  distilled  v^ater.  Standardize  this 
solution  by  the  procedure  described  below,  against  a  steel  of 
known  nickel  content  as  determined  by  the  gravimetric  dimethyl- 
glyoxime  method,  so  that  each  cubic  centimeter  is  equivalent  to 
0.05  per  cent,  of  nickel  on  the  basis  of  a  i-gram  sample  (see 
notes). 

Method. 

In  a  150-CC.  beaker  dissolve  i  gram  of  the  steel  in  20  cc.  of 
the  hydrochloric  acid,  and  add  about  2  cc.  of  nitric  acid,  specific 
gravity  1.42,  to  oxidize  the  iron.  Filter  the  solution  and  add  to 
the  filtrate  6  grams  of  tartaric  acid,  and  water  until  the  volume 
is  300  cc.  Make  the  solution  faintly  ammoniacal,  then  faintly 
acid  with  the  hydrochloric  acid,  and  cool  thoroughly.  Add  20 
cc.  of  the  dimethylglyoxime  solution  and  then  ammonium 
hydroxide,  specific  gravity  0.90,  drop  by  drop,  till  faintly  alkaline, 
stirring  vigorously.  After  standing  for  a  few  minutes,  filter  on 
a  gooch  crucible  and  wash  with  hot  water.  Dissolve  the  pre- 
cipitate on  the  filter  with  10  to  20  cc.  of  nitric  acid  (hot),  specific 
gravity  1.42,  added  drop  by  drop,  and  then  wash  five  times  with 
hot  water,  using  suction.  To  the  solution  in  a  500-cc.  beaker  add 
3  grams  of  ammonium  persulphate  and  boil  for  5  minutes.  Cool, 
make  distinctly  ammoniacal,  add  10  cc.  each  of  the  silver  nitrate 
and  potassium  iodide  solutions,  and  titrate  with  the  standard 
potassium  cyanide  solution  to  a  faint  turbidity. 

Notes. 

In  making  dimethylglyoxime  solution,  methyl  alcohol  may  be  substi- 
tuted for  ethyl  alcohol. 

Bureau  of  Standards  Standard  Steel  No.  33  is  recommended  for 
standardizing  the  potassium  cyanide  solution. 

The  weight  of  sample  taken  should  be  varied  according  to  the  nickel 
content. 


ENGINEE^RING   CHEMISTRY  I5I 

Determination  of  Chromium. 

SoivUTioNS  Re:quire:d. 

Hydrochloric  Acid. — Mix  500  cc.  of  hydrochloric  acid,  specific 
gravity  1.20,  and  500  cc.  of  distilled  water. 

Sodium  Carbonate. — A  saturated  solution;  approximately 
60  grams  of  sodium  carbonate  and  100  cc.  of  distilled  water. 

Barium  Carbonate. — Ten  grams  of  finely  divided  barium  car- 
bonate suspended  in  100  cc.  of  distilled  water. 

Standard  Sodium  Chromate. — Dissolve  2.6322  grams  of 
sodium  chromate  in  1,000  cc.  of  distilled  water.  Each  cubic  cen- 
timeter is  equivalent  to  0.02  per  cent,  of  chromium,  when  a 
5-gram  sample  is  used. 

Standard  Potassium  Permanganate. — Dissolve  2  grams  of 
potassium  permanganate  in  1,000  cc.  of  distilled  water,.  Stand- 
ardize by  using  Bureau  of  Standards  sodium  oxalate,^  and  dilute 
the  solution  with  distilled  water  so  that  i  cc.  is  equivalent  to  0.02 
per  cent,  chromium,  when  a  5-gram  sample  is  taken. 

The  factor  Na^C^O^  »-►  Cr  =  0.2584  (using  the  1913  atomic 
weights). 

ferrous  Sulphate. — Dissolve  25  grams  of  ferrous  ammonium 
sulphate  in  900  cc.  of  distilled  water  and  100  cc.  of  sulphuric 
acid  (i   :  i). 

Method. 

In  a  300-cc.  Erlenmeyer  flask,  covered,  dissolve  5  grams  of 
steel  in  50  cc.  of  the  hydrochloric  acid.  When  completely  dis- 
solved, add  gradually  the  saturated  solution  of  sodium  carbonate 
until  practically  all  the  free  acid  is  neutralized;  finish  the  neu- 
tralization with  the  barium  carbonate  suspension,  using  an  excess 
of  about  I  gram  of  the  carbonate.  Boil  the  solution  in  the  flask 
for  10  or  15  minutes,  with  the  cover  on.  Filter  the  precipitate 
rapidly  on  paper  and  wash  twice  with  hot  water.  Transfer  the 
filter  to  a  platinum  crucible  and  after  burning  off  the  paper,  fuse 
the  residue  for  10  minutes  with  a  mixture  of  5  grams  of  sodium 
carbonate  and   0.25   gram   of   potassium  nitrate.     Dissolve   the 

^  Circular  No.  40,  Bureau  of  Standards,  Oct.   i,   19 12. 


152  DNGINEKRING   CHEMISTRY 

fusion  in  water,  transfer  to  a  beaker,  add  2  cc.  of  3  per  cent, 
hydrogen  peroxide,  boil  a  few  minutes  and  filter.  Complete  the 
determination  of  chromium  in  the  filtrate  by  either  of  the  follow- 
ing procedures : 

1.  If  the  solution  is  a  strong  yellow,  add  10  cc.  of  sulphuric 
acid  (i  :  i),  and  then  the  ferrous  sulphate  solution  in  measured 
excess.  Cool  thoroughly  and  titrate  with  the  standard  potassium- 
permanganate  solution.  The  number  of  cubic  centimeters  of 
the  potassium  permanganate  solution  obtained,  subtracted  from 
the  number  corresponding  to  the  volume  of  the  ferrous  sulphate 
solution  used,  will  give  the  volume  of  the  potassium  perman- 
ganate solution  equivalent  to  the  chromium  in  the  sample. 

2.  If  the  solution  is  a  light  yellow,  cool  the  solution  and 
transfer  to  a  icmd-cc.  Nessler  tube.  To  another  Nessler  tube 
add  distilled  water,  and  from  a  burette  add  the  standard-sodium 
chromate  solution  until  the  yellow  colors  match. 

Note. 

If  procedure  No.  i  is  used,  all  hydrogen  peroxide  must  be  destroyed 
by  boiling  before  acidifying,  otherwise  chromic  acid  will  be  reduced  at 
this  stage. 


STEEL. 


References. 

"Chemical  Analysis  of  Special  Steels,  Steel-making  Alloys  and  Graphites," 

by  Charles  Morris  Johnson,  N.  Y.,  1914. 
"The  Determination  of  Chromium  and  Manganese  in  Steel,"  by  Frd.  C.  T. 

Daniels,  Jour.  Ind.  and  Eng.  Chem.,  Aug.,  1914. 
"Determination  of  Carbon  in  Steel  by  the  Direct  Combustion  Method,"  by 

Wm.  Brady,  Jour.  Ind.  and  Bng.  Chem.,  Oct.,  1914. 
"Improved    Method    for    the    Determination    of    Nitrogen    in    Steel,"    by 

L.  E.  Barton,  Jour.  Ind.  and  Bng.  Chem.,  Dec,  1914. 
"Manganese  Steel,"  by  John  H.  Hall,  Jour.  Ind.  and  Eng.  Chem.,  Feb., 

191 5. 
"Determination  of  Copper  in  Steel,"  by  W.  D.  Brown,  Jour.  Ind.  and  Eng. 

Chem.,  Mar.,  191 5. 
"Modern  Steel  Analysis,"  by  J.  A.  Pickard,  London,  1914. 
"The  Chemical  Analysis  of  Iron,"  by  A.  A.  Blair,  N.  Y.,  1913 


e:ngine:kring  chemistry  153 

Analysis  of  Tin  Plate. 

Dissolve  5  grams  of  tin  or  terne  plate  in  100  cc.  hydrochloric 
acid  (specific  gravity  i.io),  in  a  500  cc.  graduated  flask,  with 
exclusion  of  air.  When  dissolved,  cool,  and  fill  up  to  the  mark 
with  water  and  thoroughly  mix.  Transfer  50  cc.  to  a  beaker, 
and  after  adding  starch  paste,  titrate  the  tin  with  standard  iodine 
solution. 

A  convenient  strength  of  iodine  is  made  by  dissolving  5.38 
grams  of  pure  iodine  in  strong  aqueous  solution  of  potassium 
iodide  and  diluting  to  i  liter. 

For  the  iron  determination  add  mercuric  chloride  in  excess  to 
50  cc.  of  tin  plate  solution,  and  titrate  the  iron  with  standard 
bichromate. 

The  determination  of  manganese  is  quite  important,  since  it 
shows  whether  iron  or  steel  has  been  tinned. 

Treat  4  grams  of  tin  plate,  cut  into  small  pieces,  with  hot 
dilute  sulphuric  acid  for  about  15  minutes. 

When  the  iron  has  dissolved,  leaving  the  layers  of  tin  and  lead, 
add  a  little  zinc  and  allow  to  stand  for  about  2  minutes.  Filter 
and  dilute  to  20  cc. 

Take  one-half  of  this  filtrate,  add  5  cc.  nitric  acid  (specific 
gravity  1.20),  and  treat  in  the  ordinary  way  with  lead  peroxide. 

The  lead  in  tin  plate  is  best  determined  as  sulphate  after  first 
separating  the  tin  by  nitric  acid.  However,  for  ordinary  work, 
it  is  sufficiently  accurate  to  take  lead  by  difference,  allowing  0.25 
per  cent,  for  phosphorus,  carbon,  sulphur,  silicon,  etc.,  in  addi- 
tion to  the  tin,  iron  and  manganese  previously  determined. 

In  order  to  test  the  accuracy  of  the  iodine  method  for  tin,  a 
weighed  quantity  of  pure  tin,  together  with  about  forty  times 
as  much  iron,  was  dissolved  and  the  tin  titrated. 

The  result  was  as  follows : 

Tin  (gram) 

Amount  taken  0.1255 

Amount  found  0.1266 

The  following  are  a  few  analyses  that  were  made  of  British 
terne  plate  used  for  roofing : 


154 


DNGINEJ^RING   CHEjMlSTRY 


Tin 

Lead 

Iron 

Manganese  •  • 
Carbon  ] 

Phosphorus    ' 
Sulphur  i' 

Silicon,  etc.  J 


1.58 

7-97' 

89.84 

0.36 


0.25 


2.08 

7.13' 

90.23 

0.31 

0.25 


2.40 
8.89 
^8.10 
0.31 

0.25 


99-95 


3.37 
11.98 
84.18 

035 


0.25 


100.13 


1.60 
2.481 

95-31 
0.38 

0.25 


100.00 


2.54 

7.48' 

8935 

0.36 


0.25 


100.00 


1.97 

8.12^ 

89.29 
0.37 

0.25 


VIII 


1.96 

7.09 

90-55 
0.32 

0.25 


100.17 


IX 


2.56 

I0.231 

86.64 

0.32 

0.25 


The  iodine  method  may  be  used  for  determining  tin  in  all 
alloys  which  contain  no  metals  that  affect  iodine. 

However,  when  the  percentage  of  tin  exceeds  10  per  cent.,  as 
in  the  case  of  solder,  the  following  method,  although  not  quite 
so  simple  or  rapid,  is  somewhat  more  accurate. 

In  principle  the  scheme  is  simply  a  revision  of  the  well  known 
stannous  chloride  titration  method  for  iron.  Dissolve  5  grams  of 
the  tin  alloy  in  strong  hydrochloric  acid  in  a  500  cc.  graduated 
fiask,  as  in  the  case  of  tin  plate.  After  diluting  to  the  mark,  fill 
a  50  cc.  burette  with  the  solution.  Transfer  10  cc.  of  a  standard 
ferric  chloride  solution  (10  grams  of  iron  in  i  liter)  to  a  4-ounce 
flask  and  heat  to  boiling.  While  boiling  run  the  tin  alloy  solution 
cautiously  into  the  ferric  chloride  until  the  yellow  disappears. 
Cool  and  determine  the  excess  of  stannous  chloride  with  stand- 
ard iodine  solution  (Fe^Cle  +  SnCl^  .=  2^eC\^  +  SnClJ. 
Proc.  Eng.  Soc.  W.  Pa.,  82,  182. 

Method  of  Sampling  and  Analysis  of  Tin,  Terne  and 
Lead-Covered  Sheets.* 

Me:thod  of  SaMPIvING. 

Four  2  by  4-in.  pieces  are  cut,  one  from  each  side  of  the  sheet, 
parallel  with  the  sides  and  equidistant  from  the  ends,  as  shown 
in  Fig.  21.  One  sheet  from  each  grade  or  shipment  is  taken  for 
analysis. 

These  samples,  before  weighing,  should  be  thoroughly  cleaned 

^  By  difference. 

*  Proceedings  Amer.  Soc.  Testing  Materials,  J.  A.  Aupperle. 


ENGINEERING   CHEMISTRY 


155 


with  chloroform,  carbon  tetrachloride  or  gasoline.  Each  piece  is 
then  cut  in  half,  marking  one  half  "A"  and  the  other  half  "B." 
The  four  pieces  comprising  lot  A  are  then  accurately  weighed 
together,  cut  into  small  pieces  about  Ys  inch  square,  thoroughly 
mixed,  and  used  for  the  determination  of  tin  and  lead.  The 
four  pieces  comprising  lot  B  are  reserved  for  the  analysis  of 
base  metal  and  the  direct  determination  of  coating  as  a  check  on 
the  analysis  of  lot  A. 


"^ 


k-.--4-- 
28' 


■2       n 

i<-2>| 


/4  ■■ 


j-r 


M 


s  : 

TT 

<::> 

CV4 

i 
i 
j 

1 

1 

it- 

"    1 

•> 

Fig.   21. 

A  templet  should  be  provided,  made  preferably  from  steel 
ys  inch  thick  and  exactly  2  by  4  inches.  A  scribe  is  used  to  ac- 
curately mark  the  sections  to  be  cut.  The  templet  is  then  used 
to  subdivide  the  2  by  4-inch  specimens  into  two  pieces,  2  by  2 
inches.  The  sections  for  analysis  are  then  cut  with  tinner's 
shears. 

Determination  of  Tin. 

Three  5-gram  portions  of  the  finely  cut  sample  of  lot  A  are 
placed  into  three  300-cc.  Erlenmeyer  flasks,  each  fitted  with  a 
one-hole  rubber,  stopper  containing  a  glass  tube  bent  twice  at 
right  angles,  one  end  of  which  projects  through  the  rubber 
stopper  for  a  short  distance,  the  other  end  being  long  enough 


156  Engine;e)ring  chemistry 

to  reach  almost  to  the  bottom  of  a  beaker,  placed  on  a  level  with 
the  flask,  containing  about  300  cc.  of  dilute  sodium-bicarbonate 
solution.  Add  75  cc.  of  concentrated  hydrochloric  acid,  connect 
the  flask  with  the  stopper  containing  the  glass  tube,  and  place 
the  flask  on  a  hot  plate.  Heat  gradually  at  first  until  most  of 
the  metal  is  in  solution.  The  long  end  of  the  glass  tube,  in  the 
meantime,  is  submerged  in  the  beaker.  The  hydrochloric  acid 
solution  is  finally  brought  to  boiling  and  when  all  the  metal  is 
dissolved  the  beaker  containing  dilute  sodium  bicarbonate  solu- 
tion is  replaced  by  one  containing  a  saturated  solution  of  the 
same.  Remove  the  beaker  and  flask  to  a  cool  place.  This  will 
cause  a  small  amount  of  the  sodium  bicarbonate  to  enter  the 
flask  and  exclude  the  air.  The  solution  is  finally  brought  to  a 
low  temperature,  preferably  with  ice  water.  This  solution  is 
then  diluted  to  about  200  cc.  with  oxygen- free  water  which  con- 
tains several  cubic  centimeters  of  starch  solution,  and  titrated 
with  N/20  iodine  solution.  We  have  found  this  strength  of 
iodine  solution  to  be  the  most  satisfactory  for  this  method. 

The  distilled  water  free  from  oxygen  is  obtained  in  any  of 
three  ways :  ( i )  By  passing  carbon  dioxide  through  the  cold 
distilled  water;  (2)  by  boiling  vigorously  and  cooling;  or  (3)  by 
adding  a  few  cubic  centimeters  of  concentrated  hydrochloric 
acid  to  the  water  and  then  about  2  grams  of  sodium  bicarbonate, 
stirring  vigorously.  By  running  this  determination  in  triplicate, 
the  first  titration  serves  as  a  control  to  indicate  the  number  of 
cubic  centimeters  of  iodine  required,  whence  the  two  succeeding 
titrations  may  be  made  very  rapidly  and  should  check  very 
closely. 

Standardizing  the  Iodine  Solution. — About  o.i  gram  of  pure 
tin  and  4  grams  of  iron  filings  are  dissolved  in  75  cc.  of  concen- 
trated hydrochloric  acid,  etc.,  as  under  the  determination  of  tin. 
One  cubic  centimeter  of  N/20  iodine  ^  0.002975  gram  of  tin. 

Calculation. — Weight  of  tin: 

Wt.  of  tin  on  5  g.  X  Wt.  (g.)  of  16  sq.  in.  ^  _   .         _ 

■  ~~ X  0.0421  — 

o 

number  of  pounds  per  case  of  112  sheets,  20  by  28  in. 


DNGlNEEiRING   CHEJMISTRY  1 57 

Determination  of  Lead. 

Dissolve  lo  grams  of  the  finely  cut  sample  of  lot  A  in  150  cc. 
nitric  acid  ( i  :  i ) .  Heat  until  free  from  brown  fumes  and  dilute 
to  I  liter  and  mix  thoroughly.  Take  100  cc.  of  this  solution, 
add  10  cc.  of  concentrated  nitric  acid,  electrolyze  at  a  tempera- 
ture of  50  to  60°  C,  using  I  to  2  amperes  and  2.3  to  2.5  volts. 
The  weight  of  Pb02  is  multiplied  by  0.866. 
Calculation. — Weight  of  lead  : 

PbO^  found  (g.)  X  0.866  X  20  =  Pb  ; 
Pb  X  Wt.  (g.)  of  16  sq.  in.    ^  ^  ^ 

X     8.6421    := 

10  ^ 

number  of  pounds  per  case  of  112  sheets,  20  by  28  in. 

Direct  Determination  of  the  Weight  of  Coating. 

The  remaining  four  pieces  representing  lot  B  are  used  for 
the  analysis  of  the  base  metal  and  incidentally  can  be  used  for 
the  direct  determination  of  the  weight  of  coating. 

The  four  2  by  2-inch  pieces  are  carefully  weighed  together 
and  each  piece  is  wrapped  with  a  stiff  platinum  or  nickel  wire 
in  such  a  manner  that  it  may  be  placed  in  the  acid  in  a  horizontal 
position.  Heat  60  cc.  of  concentrated  sulphuric  acid  contained 
in  a  400-cc.  Jena  glass  beaker  to  at  least  250°  C,  immerse  each 
piece  separately  in  the  hot  acid  for  exactly  i  minute,  and  remove 
to  a  600-cc.  Jena  beaker  containing  50  cc.  of  distilled  water. 
Immerse  momentarily  and  rub  the  surface  while  washing  with 
about  50  cc.  more  of  distilled  water,  using  a  wash  bottle  for  this 
purpose.  The  four  samples  are  thoroughly  dried,  reweighed, 
and  used  for  the  analysis  of  base  metal. ^ 

The  loss  in  weight  represents  the  coating  and  some  iron.  The 
sulphuric  acid  contained  in  the  400  cc.  beaker  is  cooled  and  com- 
bined with  the  washings  in  the  600  cc.  beaker.  Two  hundred 
cubic  centimeters  of  concentrated  hydrochloric  acid  are  added 
and  the  solution  boiled  for  a  few  minutes.  The  solution  is  cooled, 
poured  into  a  graduated  500  cc.  flask  and  filled  to  the  mark  with 
distilled  water. 

^  The  methods  of  analysis  of  the  base  metal  are  outside  the  scope  of  this  paper 
and  will  not  be  given. 


158  e:ngine:e;ring  chemistry 

Determination  of  Iron. 

Place  100  cc.  of  this  solution  in  a  300-cc.  Erlenmeyer  flask, 
add  I  cc.  of  a  saturated  solution  of  potassium  permanganate  to 
oxidize  the  iron  and  tin,  heat  to  boiling  and  reduce  with  a  few- 
drops  of  stannous  chloride.  Cool,  pour  into  a  liter  beaker  con- 
taining 400  cc.  of  distilled  water,  add  25  cc.  of  mercuric  chloride, 
followed  by  10  cc.  of  phosphoric  acid  and  manganese  sulphate 
solution,  and  titrate  with  N/io  potassium  permanganate. 

Calculation. — 

Grams. 

Four  pieces  2  by  2  in.  weigh 28.5686 

Same  after  stripped  in  acid 24.1620 

Loss,  coating  plus  iron 4.4066 

Iron  as  found  by  titration 0.4887 

Weight  of  coating 3.9179 

3.9179  X  8.6421  z=  number  of  pounds  per  case  of  112  sheets,  20  by  28  in. 

Tin  in  100  cc.  X  5  X  100  ^  .^. 

. ^ =  percentage  of  tin. 

Weight  of  coating  '^ 

PbOo  (in  100  cc.)  X  0.866  X  10  X  100  ,  -,      , 

^-^ — „,  .       '  \. — — — ■  =  percentage  of  lead. 

Weight  of  coatmg 

In  the  analysis  of  tin  plate,  the  weight  of  coating  is  expressed 
in  pounds  per  box,  which  is  a  half  case,  or  112  sheets  14  by  20 
inches;  hence  to  obtain  the  weight  of  coating  per  box  on  tin 
plate,  the  number  of  pounds  as  obtained  above  is  divided  by  2. 

The  remainder  of  the  solution  which  has  been  used  for  the 
determination  of  iron  can  be  used  for  the  determination  of  tin 
as  follows :  Place  three  portions  of  100  cc.  each  in  three  300-cc. 
Erlenmeyer  flasks.  If  any  of  the  lead  sulphate  should  or  should 
not  be  removed  in  any  of  these  portions,  the  accuracy  of  the  tin 
determination  is  not  affected.  Add  i  gram  of  powdered  anti- 
mony, connect  with  rubber  stopper  and  glass  tube  described  in 
the  method  of  determination  of  tin  in  the  sample  of  lot  A,  place 
on  a  hot  plate,  using  dilute  sodium  bicarbonate  solution  as  a 
trap,  and  heat  until  the  solution  becomes  decolorized.     Replace 


ENGINE^ERING   CHE:mISTRY 


159 


the  dilute  sodium  bicarbonate  solution  with  a  saturated  solution 
of  the  same,  remove  from  the  hot  plate,  cool,  dilute  and  complete 
the  determination  as  described  under  the  first  method. 

Specifications. 

Ternepi^ate  (Rooeing  Tin). 

All    roofing   tin   to   be    made   of    best   quality    soft    steel    as    a   basis, 
resquared,  112  sheets  to  the  box. 


Black  plate  from  which 
made  to  weigh  per 
112  sheets  net  in  the 
black 

Tin  when  finished  to 
weigh  per  112  sheets 
net 


IC  14  by  20 
inches 


Pounds 

95  to  100 
115  to  120 


IC  28  by  20 
inches 


Pounds 

195  to  200 
235  to  240 


IX  14  by  : 
inches 


Pounds 

125  to  130 
145  to  150 


IX  28  by  20 
inches 


Pounds 

250  to  255 
290  to  295 


1.  Coating  on  all  roofing  tin  to  be  a  mixture  of  pure  new  tin  and 
pure  new  lead,  thoroughly  mixed  and  having  a  proportion  of  not  less  than 
20  per  cent,  of  tin  and  the  balance  lead ;  coating  to  be  thoroughly  amal- 
gamated with  the  black  plate  by  the  palm  oil  process. 

2.  This  coating  must  be  applied  so  that  the  sheets  be  evenly  and 
equally  coated  on  both  sides  and  the  coating  distributed  equally  over  each 
sheet. 

3.  After  the  plate  has  been  cleansed  in  a  weak  acid  solution,  it  is  to 
be  thoroughly  washed  with  water,  after  which  nothing  is  to  be  brought 
in  contact  with  the  black  plate  but  pure  palm  oil,  pure  new  tin,  and  pure 
new  lead. 

4.  Every  sheet  so  coated  must  be  free  from  all  defects,  blisters,  bad 
edges  and  corners,  and  bare  or  imperfectly  coated  spots. 

Each  sheet  to  be  stamped  with  the  brand,  thickness  of  the  plate,  and 
name  of  the  manufacturer. 

An  affidavit  to  the  above  must  be  furnished  by  both  the  successful 
bidder  and  the  superintendent  of  the  works  where  the  plates  are  made, 
which  affidavit  must  accompany  the  delivery  of  the  roofing  tin. 

Tinned  Pirate  (Bright  Tin). 
All  tin  to  be  made  of  best  quahty  soft  steel  as  a  basis,  112  sheets  to 
the  box. 


i6o 


ENGINEERING   CHEMISTRY 


Black  plate  from  which  made  to 
weigh  per  112  sheets  net  in  the 
black 

Tin  when  finished  to  weigh  per  112 
sheets  net 


IC  14  by  20 
inches 


Pounds 

103 

108 


IXX  14  by  20 
inches 


Pounds 

155 
160 


IXXXXi4by2o 
inches 


Pounds 
200 


A  margin  of  2^2  per  cent,  less  than  that  specified  will  be  allowed, 
provided  it  can  be  shown  by  the  contractor  that  he  has  endeavored  to 
comply  with  the  specifications  regarding  the  weight  of  tin  required. 

The  tin  is  to  be  of  the  best  quality  of  Straits,  Malacca,  or  Australian. 
If  other  size  sheets  are  required,  the  sample  proportions  of  black  plate  and 
tin  should  be  observed. 

The  coating  is  to  be  thoroughly  amalgamated  with  the  black  plate. 
This  coating  must  be  applied  so  that  the  sheets  be  evenly  and  equally 
coated  on  both  sides  and  the  coating  distributed  equally  over  each  sheet. 
Every  sheet  so  coated  must  be  free  from  all  defects,  blisters,  bad  edges 
and  corners,  and  bare  or  imperfectly  coated  spots. 


ALLOYS. 


This  subject  may  be  divided  into  three  classes: 

1.  Alloys  composed  principally  of  copper  and  zinc,  or  of  cop- 
per, tin  and  zinc,  or  tin  and  lead. 

2.  Alloys  or  compositions  in  which  copper,  tin,  lead,  or  anti- 
mony are  constituents. 

3.  Alloys  not  included  in  the  first  two  divisions. 

Alloys  of  the  first  class  may  comprise  brass,  bronze,  bell  metal, 
gun  metal,  Muntz's  metal,  bar  solder  (i^  lead,  ^  tin),  etc.  The 
analysis  may  be  performed  as  follows  (if  composed  of  copper 
and  zinc  only)  :  Transfer  i  gram  of  the  brass  to  a  No.  3  beaker 
covered  with  a  watch  glass,  and  add  gradually  25  cc.  nitric  acid ; 
when  solution  is  complete,  remove  watch  glass,  after  washing, 
allow  solution  to  cool,  transfer  it  to  a  250-cc.  flask,  and  add 
water  to  the  containing  mark.  Mix  thoroughly  (the  solution 
being  at  15°  C),  and  transfer  50  cc.  of  the  solution  to  a  No.  3 
beaker,  dilute  sufficiently  with  water  and  precipitate  the  copper 


ENGINEE^RING    CHEMISTRY  .  l6l 

electrically.  Upon  complete  precipitation  of  the  copper,  the  plati- 
num cone  and  spiral  are  removed  from  the  solution,  washed  with 
water,  and  the  washings  added  to  the  solution  in  the  beaker.  Add 
a  few  drops  of  nitric  acid  to  the  solution,  boil  and  precipitate  the 
zinc  with  a  slight  excess  of  sodium  carbonate.  Boil,  filter,  wash 
well  with  hot  water,  dry,  ignite,  and  weigh  as  ZnO. 

Example :  One  gram  brass  turnings  taken.  Solution  250  cc. 
Fifty  cubic  centimeters  of  solution  taken : 

Grams 

Platinum  cone  -f-  Cn 28.175 

Platinum  cone    29.995 

Cu    0.160 

0.160  X  5  X  100       -  ^  ^ 
—  80  per  cent.  Cu. 

Grams 

Porcelain  crucible  -f  ZnO 17.655 

Porcelain  crucible  17.605 

ZnO    0.050 

0.050  X  65  ^       0.040  X  5  X  100 

- — ^ ^  =0.040  Zn.    — =  20  per  cent. 

81  I  ^ 

Per  cent. 

Cu    ; 80 

Zn   20 

Total   100 

Where  tin  is  also  a  component,  the  above  method  is  varied  as 
follows : 

Take  I  gram  of  the  fine  turnings  and  digest  with  nitric  acid  as 
above.  Evaporate  nearly  to  dryness,  add  50  cc.  warm  water, 
filter  by  decantation  into  a  250-cc.  flask,  washing  the  precipitate 
thoroughly  with  hot  water,  dry  it,  ignite  and  weigh  as  SnOg, 
and  calculate  to  Sn. 

The  filtrate  is  made  up  to  250  cc.  with  water  (15°  C),  thor- 
oughly mixed,  and  50  cc.  taken  for  copper  and  zinc  as  before. 
II 


i62  ^ngine;e;ring  chejmistry 


Grams 

Porcelain  crucible  -f-  Sn02 16.6743 

Porcelain  crucible    16.5220 

Sn02    0.1523 

Sn  =  12  per  cent. 

Grams 

Platinum  cone  +   Cu 28.115 

Platinum  cone    27.995 

Cu  0.120 

Cu  =  60  per  cent. 

Grams 

Porcelain  crucible  +  ZnO .  .  . '. 17.6750 

Porcelain  crucible 1 7.6052 

ZnO   0.0698 

Zn  =  28  per  cent. 

Resume. 

Per  cent. 

Sn    12 

Cu    • 60 

Zn   28 

Total   100 

For  a  method  for  the  complete  analysis  of  brass  including 
iron,  and  antimony,  consult  article  by.  Albert  J.  Hall,  Electro- 
chemical &  Metallurgical  Industry,  Nov.,  1908,  pp.  444-446. 

The  Estimation  of  Copper  in  Copper  Slags.^ 

Weigh  5  or  10  grams  of  the  slag  into  a  No.  3  beaker,  add 
100  cc.  hot  water,  cover  and  boil  on  iron  plate.  Add  30  cc.  of 
HCl,  5  cc.  at  intervals  of  about  a  minute,  rotating  the  beaker  to 
prevent  sticking.  When  the  HCl  is  all  added  continue  the  boil- 
ing for  5  minutes,  remove  from  the  plate,  add  an  additional 
100  cc.  of  hot  water  and  conduct  into  the  solution  a  rapid  stream 
of  H^S  for  5  minutes.  Filter  under  exhaust  through  a  porcelain 
gooch  crucible,  using  a  paper  disc  in  the  bottom  thereof  and 
wash  three  times  with  water  containing  a  little  H2S.     It  is  not 

1  Thorn    Smith     (Research    Chemist,    Ducktown    Copper    Works,    Tenn.),     Chem. 
Engineer. 


ENGINE^ERING   CHEMISTRY 


163 


necessary  to  remove  all  of  the  precipitate  from  the  beaker.  Put 
the  gooch  crucible  and  contents  back  into  the  beaker,  add  10  cc. 
HNO3  containing  a  little  Br  and  nitrous  acid,  then  add  20  cc.  of 
ammonia  and  titrate  with  cyanide,  filtering,  if  desirable  first. 
Or  better,  neutralize  the  acid  solution  with  ammonia,  add  2  cc. 
each  of  HNO3  and  H^SO^  and  electrolyze.  (Most  slags  of  this 
character  filter  through  the  gooch  crucible  with  difficulty  owing 
to  the  small  amount  of  colloidal  silica  present.  In  such  cases  the 
addition  of  a  few  drops  of  i  to  i  HF  will  expedite  the  filtra- 
tion.) 


ExAMPi.Es  oj?  Alloys  oe  the  First  Ceass. 


Bell  metal 

Brass 

Brass  (yellow) 

Speculum  metal 

Delta  metal  or  "Sterro 
Muntz  metal  

Mosiac  gold 

Gun  metal 

Pinchbeck 

{  Mannheim  ) 

;  Gold      / 


Tin 
Parts 


33.4 


Cu. 
65.0 
91.0 
83.0 

80.0 


Copper 
Parts 


78.0 
72.0 
60.0 
66.6 
60.0 
60.0 
Zn. 

35 -o 
17.0 
20.0 


zinc 
Parts 


28.0 
40.0 

38.2  (*i.8  Fe) 
40.0 
Sn. 

90 


The  Good  Effect  of  Deoxidizing  Brass  and  Bronze  Scrap 
and  New  Metal  by  Magnesium. 

Magnesium  has  now  become  one  of  the  agents  for  deoxidizing 
metals,  and  manufacturers  are  beginning  to  realize  that  it  is 
advantageous  in  melting  various  scrap.  On  account  of  the  fact 
that  it  is  a  metal  and  not  a  non-metallic  element  like  phosphorus, 
a  slight  excess  over  and  above  that  necessary  to  deoxidize  the 
metal  is  not  injurious. 

Some  experiments  were  recently  made  in  Germany  on  the  ef- 
fect of  magnesium  upon  both  scrap  brass  and  bronze  and  new 
metal,  and  the  results  indicate  that  the  castings  were  greatly 
improved.    These  results  are  given  below. 


164 


ENGINEERING  CHEMISTRY 


The  quantity  of  magnesium  used,  0.05  per  cent.,  has  been 
found  ample  for  the  deoxidizing.  It  is  an  error  to  employ 
more,  and  many  of  the  unsatisfactory  results  have  been  brought 
about  by  using  an  excess. 


TABI.E  Showing  Results  oe  Tests  Made  on  Brass,  Red  Metai.  and 
Bronze,  Both  With  and  Without  Magnesium 


No 

Alloy 

Composition 
of  the 
Alloy 

Original  Dimen- 
sions of  Test  Bars 

Tensile  Strength 

Elon- 
gation 
Per 
Cent. 

Diameter 
in  inches 

SecMArea 
in  sq.  in. 

I.bs. 

Lbs. 
sq.  in. 

As 
A5 

Brass 

90% 

Scrap  Brass, 

Gates  and 

Sprues 

10% 

Zinc 

.976 
.988 

.748 
.766 

11,968 
12,540 

16,000 
16,300 

3.2 
2.8 

As  melted 

A  6 
A  6 

925 

948 

.672 
705 

15,378 
15,136 

22,800 
21,400 

3.5 
4.5 

Deoxidized 
with  0.05^0 
Magnesium 

C  I 
C  I 

Brass 

All  Scrap, 
Consisting  of 
Chips,  Filings 
and  Grindings 

972 
.976 

.742 
.748 

12,144 
13,112 

16,300 
17,500- 

I.O 
2.0 

As  melted 

C  2 
C  2 

.976 
.976 

.748 

.748 

20,280 
20,416 

27,100 
27,200 

7-5 
6.5 

Deoxidized 
with  0.05% 
Magnesium 

B  4 
B  4 

Red 
Brass 

95% 

Scrap  Red 

Brass  in 

Form  of  Gates 

Sprues,  etc. 

5% 
Zinc 

968 
976 

736 

748 

15,202 
13,640 

20,600 
18,200 

5.0 
3-0 

As  melted 

B  3 
B  3 

.976 
.976 

•748 
.748 

21,846 
20,790 

29,200 
27,800 

8.0 
7.0 

Deoxidized 
with  0.05^ 
Magnesium 

D  I 
D  I 

Bronze 

90% 
Copper 
and 
10% 
Tin 

.968 
.964 

.736 
.728 

18,700 
18,458 

25,400 
25,300 

lO.O 

8.0 

As  melted 

D  2 
D  2 

.964 
.964 

.728 
.728 

23,100 
23,232 

31,700 
31,900 

13-0 
12.0 

Deoxidized 
with  0.05 9& 
Magnesium 

ENGINEE^RING    CHE^MISTRY 


165 


According  to  these  tests,  the  strength  of  the  test  bars  was 
increased  from  30  to  40  per  cent.,  and  the  elongation  from  40 
to  60  per  cent. 

Alloys  of  the  second  class  may  comprise  Babbitt  metal, 
Britannia  metal,  type  metal,  white  metal,  camelia  metal,  Tobin 
bronze,  ajax  metal,  car-box  metal,  manganese  bronze,  magnolia 
metal,  etc. 


ExAMPi^Es  OF  Ar.i.0Ys  OF  THE  Second  Class. 


Iron 

Tin 

Anti- 
mony 

I,ead 

Copper 

Zinc 

Bis- 
muth 

Phos. 

Babbitt  metal 

45-5 
90.0 
80.0 
85.0 
77.8 
5U.O 
40.0 
0.9 

lO.O 

12.40 

4-75 
22.90 

4-25 
10.98 

45-50 

8.00 

16.6 

82.0 

3-0 

13.00 
10,00 

14.5 
19.4 

5-0 
15.0 

^4.38 

40.0 

1-5 

Pewter  ••• 

20.0 

A  Qhhnrv  m*^tn  1  ......  . 

2.8 

Soft  solder 

50.0 

550 

0.4 

9-5 

227 
80.0 
27.10 
H.75 

7-37 
84-33 

0.2 

61.2 
79.70 
82.67 
trace 

37.3 

PViosr^Virtr  Vtrnnyf^  .... 



0.8 
0.005 

Deoxidized  bronze  •  •  • 

IVTjjcrnol  1  a   mftal  .  .     ... 

0.20 

2.45 

0.25 
50.0 

"•55 

70.20 
81.28 

34.1 

77.0 

4.4 

6  0 

10.20 

0.68 
20.4 

Aiav    TTiftal 



0.37 

Oar-V»r»Y  mptnl    ....... 

o.6i 

Pjir«jr>n'«  ■tjeViitf   mftal  . 



"B"  alloy,  P.  R.  R... 

•....• 

15.00 

trace 

80.0 

White  metal 

12.0 
15.0 

82.0 
99-7 

Tvne          "      

Shot          "      



ars.0.3 

Analysis  of  Babbitt  Metal.^ 

Two  grams  of  drillings  in  an  8-ounce  beaker  are  treated  with 
30  cc.  nitric  acid  (specific  gravity  1.20)  and  heated  till  decom- 
position is  complete  and  the  free  acid  nearly  all  evaporated. 
When  about  5  cc.  of  the  solution  remain,  add  15  cc.  of  water, 
and  then  add  concentrated  sodium  hydroxide  solution  till  nearly 
neutral ;  50  cc.  of  sodium  sulphide  solution  are  then  added, 
the  mixture  well  stirred,  and  then  boiled  gently  for  ^   hour. 


^  Some  varieties  of  Delta  metal  contain 
^  Method  of  E.  M.  Bruce,  modified. 


to  2  per  cent,  of  tin. 


l66  '        ENGINEJDRING   CHEMISTRY 

The  solution  then  contains  the  tin  and  antimony.  The  precip- 
itate, which  contains  the  sulphides  of  lead  and  copper,  is  filtered 
on  a  9-centimeter  Swedish  filter,  and  washed  thoroughly  with 
water  containing  i  per  cent,  of  the  above  sodium  sulphide  solu- 
tion.   The  filtrate  is  received  in  a  300  cc.  beaker. 

Tin  and  Antimony. — The  filtrate  is  diluted  to  200  cc.  and 
boiled.  Crystals  of  oxalic  acid,  C.  P.,  are  cautiously  added  till 
the  sodium  sulphide  is  all  decomposed  and  a  milky  separation 
appears,  mixed  with  a  precipitate  which  is  usually  at  first 
black.  Boil  for  20  minutes.  Pass  hydrogen  sulphide  for  10  min- 
utes. Filter  rapidly  on  a  gooch  crucible  and  wash  with  hot 
water.  Dry  and  heat  crucible  and  contents  in  a  stream  of  carbon 
dioxide  to  a  temperature  above  300°  C.  for  one  hour.  Cool  in 
carbon  dioxide,  remove  crucible  and  weigh  as  Sb^Sg.  The  gooch 
crucible  containing  the  Sb^Ss  +  S  may  be  treated  with  alcohol, 
then  carbon  disulphide,  (in  order  to  remove  the  sulphur),  then 
alcohol  dried  and  weighed,  instead  of  igniting  in  carbon  dioxide. 
SKSs  X  0.71390  z=  Sb. 

The  filtrate  from  the  SbgSg  is  treated  with  30  cc.  concentrated 
sulphuric  acid  and  boiled  down  till  all  oxalic  acid  is  decomposed 
and  strong  fumes  of  sulphuric  acid  come  off.  Cool.  Dilute  cau- 
tiously to  200  cc,  mix  well  and  filter  quickly.  Dilute  filtrate  to 
300  cc,  warm  slightly  and  pass  hydrogen  sulphide.  Filter  stan- 
nous sulphide  and  wash  with  hot  water.  Dry,  ignite,  and  weigh 
as  stannic  oxide  in  porcelain  crucible.     SnO^  X  0.788  ■=^  Sn. 

The  copper  and  lead  sulphide  precipitate  is  washed  off  the 
filter,  treated  with  dilute  nitric  acid,  warmed  till  decomposed, 
and  the  sulphur  filtered  off.  The  lead  is  then  separated  as  sul- 
phate by  evaporation  with  sulphuric  acid.  The  lead  sulphate  is 
filtered  on  a  gooch  crucible,  washed  with  water  containing  5 
per  cent,  sulphuric  acid,  dried,  and  ignited  over  a  Bunsen  burner. 
PbSO^  X  0.68298  ,=  Pb. 

The  copper  is  separated  from  the  filtrate  by  hydrogen  sulphide. 
The  sulphide  is  decomposed  by  nitric  acid,  and  the  resulting 
solution  titrated  or  electrolyzed. 

Sodium  sulphide  solution  for  Babbitt  analysis  is  made  up  as 


DNGINEEJRING   CHEMISTRY  167 

follows :  One  pound  sodium  sulphide  crystals  are  dissolved  in  2 
liters  of  water.  Portions  of  this  are  from  time  to  time  saturated 
with  hydrogen  sulphide  gas  and  filtered  for  use. 

Separation  of  Tin  and  Antimony  in  Alloys. 

Mengin  treats  the  alloy  (for  instance,  anti-friction  metal)  with 
nitric  acid  (1.15),  collects  the  insoluble  oxides  of  tin  and  anti- 
mony, w^ashes,  carefully  ignites  and  weighs  them,  =1  M.  The 
mixed  oxides  are  next  suspended  in  hydrochloric  acid  and  water 
and  a  ball  or  plate  of  pure  tin  added,  whereupon  the  antimony  is 
reduced  to  metal  and  the  tin  converted  into  chloride;  the  reac- 
tion is  best  accelerated  by  heat,  about  3  hours  being  necessary 
for  2  grams  of  the  oxides.  The  precipitated  antimony  is  washed 
by  decantation  with  water,  then  with  alcohol,  dried  and  weighed 
=^  A.  There  is  no  appreciable  oxidation  of  the  antimony  and 
the  method  is  very  exact.    The  tin  is  estimated  by  difference. 

M  —  Ax  1.262  =  weight  of  tin  oxide;  the  latter  multiplied 
by  0.7888  gives  the  weight  of  tin  in  the  alloy.  An  alternative 
method  for  the  estimation  of  the  tin  is  to  precipitate  the  latter 
by  zinc.  The  following  figures  (indicating  grams)  of  an  analysis, 
show  the  accuracy  of  the  method : 

Samples  taken  Oxides  found  Metals  found 

Sn 1. 162  )  (         Sn 1. 154 

Sb 1.312  ^      -^-  ^       I         sb ..1.309 

Third  Class  May  Comprise. 

Aluminum  bronze Al  7.3,  Si  6.5,  Cu  86.2,  or  Al  10,  Cu  90 

Ferro-aluminum Al  1.25,  Fe,  etc.,  99.75,  or  Al  12.50,  Fe,  etc.,  87.50 

Ferro-tungsten Fe  43.4,  W  53.1,  Mn  3.5 

German  silver Cu  50,  Ni  14.8,  Sn  3.1,  Zn  31.9 

Rosine Ni  40,  Ag  10,  Al  30,  Sn  20 

Metalline Co  35,  Al  25,  Cu  30,  Fe  10 

Aluminum  "bourbounz" Al  85.74,  Sn  12.94,  Si  1.32 

Silicon  bronze Fe,  etc.,  86.59,  Si  13.41 

Guthrie's  "Eutectic" Cd  14.03,  Sn  21.10,  Pb  20.55,  Bi  50 

Arsenic  bronze Cu  79.70,  Sn  10,  Pb  9.50,  As  0.80 

Manganese  bronze Cu  88,  Sn  10,  Mn  2 

Packf ong Cu  44,  Ni  16,  Zn  40 

The    following  new   alloys   are   mentioned   by   A.    M.    Farlie, 


i68  Engine:ering  chemistry 

chemist,  Tennessee  Copper  Co.,  in  the  journal  of  Metal  Industry, 
Sept.,  1906: 

"Cupro  Magnesium" Copper  90%,  Magnesium  10% 

Hydraulic  bronze Copper  75%,  Zinc  14%,  Tin  11% 

Hardware  metal. .. Copper  50%,  Zinc  34.9%,  Aluminum  0.10%,  Nickel  15% 

"Phono-Electric"  Mare Copper  98.55%,  Tin  1.4%,  Silicon  0.05% 

Sterline Copper  68.52%,  Zinc  12.84%,  Nickel  17.88%,  Iron  0.76% 

Platinoid Copper  54.04%,  Zinc  20.42%,  Lead  0.15%,  Nickel  24.77% 

Iron  0.47%,  Manganese  0.15% 

Manganese  resistance  metal Cu  85%,  Iron  3%,  Manganese  12% 

Manganin. .  .Copper  82.12%,  Nickel  2.29%,  Iron  0.57%,  Manganese  15.02% 

Trolley  wheel  bronze Copper  92%,  Zinc  2%,  Tin  6% 

Hydraulic  metal Copper  83.05%,  Nickel  6%,  Iron  10.81%,  Lead  0.10% 

Acid-resisting  metal Copper  82%,  Zinc  2%,  Tin  8%,  Lead  8% 

Victor  metal Copper  49.94%,  Nickel  34.27%,  Zinc  15.40% 

Aluminum  0.11%,  Iron  0.28% 

Needle  metal Copper  84.96%,  Zinc  5.31%,  Tin  7.96%,  Lead  1.77% 

Pattern  bronze Copper  90%,  Zinc  2.50%,  Tin  6.00%,  Lead  1.50% 

Turbine  wheel  mixture.  .Copper  86.77%,  Zinc  3.48%,  Tin  8.68%,  Lead  1.07% 
Aluminum  silver Copper  57%,  Zinc  20%,  Nickel  20%,  Al  3% 

Cuprum  magnesium  is  used  in  the  proportion  of  i  pound  to 
100  pounds  of  copper  as  a  deoxidizing  agent.  Impairs  the  con- 
ductivity of  copper  less  than  silicon  or  any  other  deoxidizer. 

''Hydraulic  bronze"  is  a  metal  especially  adapted  for  steam  uses. 

''Phono-electric  wire"  is  used  for  trolley  wire,  telephone  wire, 
etc.  It  has  a  much  higher  tensile  strength  than  pure  copper, 
but  only  40  per  cent,  of  its  conductivity.  In  the  manufacture  of 
the  alloy,  the  silicon  is  nearly  all  slagged  off,  consequently  little 
or  none  can  be  found  in  the  finished  wire  by  chemical  analysis. 

"Sterline"  a  white  metal,  but  classed  among  the  copper  alloys 
on  account  of  its  high  copper  tenor.  It  is  used  as  an  imitation 
silver. 

New  White  Metai,  Ai^lgys. 

Kayserzinn Copper  1.58%,  Tin  92.98%,  Antimony  5.44% 

Tempered  lead Tin  0.98%,  Lead  98.51%,  Antimony  0.11%,  Sodium  1.3% 

Improved  Britannia  metal Copper  2.31%,  Tin  90.10%,  An  7.44% 

Mn  0.15% 
Soft  bearing  metal Copper  0.42%,  Tin  11.40%,  Lead  80.65% 

Antimony  7.53% 

Alkali-resisting  alloy Nickel  5.0%,  Iron  95% 

White  brass Copper  2%,  Zinc  34%,  Tin  64% 


EjNGINIvERING   CHEMISTRY  169 

Platinoid  is  used  largely  in  the  manufacture  of  electrical  in- 
struments. 

'  Manganese  resistance  metal  is  used  as  a  resistance  material 
in  place  of  German  silver.  The  electrical  conductivity  is  only  3 
to  4.5  per  cent,  that  of  copper. 

Manganin  is  used  as  resistance  material.  The  nickel  increases 
the  melting  point,  permitting  a  higher  heat  v^ithout  danger  of 
fusing.  The  nickel  also  decreases  the  temperature  coefficient  of 
the  electrical  resistance. 

Trolley  Wire  Bronze. — The  name  implies  the  use.  The  zinc 
is  added  to  give  solidity  to  the  casting.  The  introduction  of  lead 
into  the  alloy  results  in  increased  wear. 

Hydraulic  metal  resists  the  action  of  acid  mine  water  better 
than  either  red  brass,  muntz  metal,  copper-tin  bronze,  or  man- 
ganese bronze.     It  is  remelted  once  before  using. 

Acid-resisting  metal,  said  to  be  the  best  strong  metal  for 
resisting  the  action  of  acid,  the  lead  alloys  being  too  soft  for 
many  purposes.  Phosphorus  is  added  in  the  form  of  phosphor- 
tin,  0.125  pound  of  5  per  cent,  phosphor-tin  to  every  loo  pounds 
of  the  alloy.  Any  excess  of  phosphor-tin  over  the  amount  speci- 
fied with  result  in  blow  holes.  The  phosphor-tin  is  added  last, 
and  the  metal  is  cast  at  the  lowest  temperature  at  which  it  will 
run.  The  mixture  is  reported  to  be  particularly  useful  for  sul- 
phite pulp  mill  fittings.     It  will  resist  the  action  of  nitric  acid. 

Victor  metal,  another  white  metal  high  in  copper.  It  is  whiter 
than  German  silver,  but  cannot  be  rolled.  It  withstands  the 
action  of  salt  air  and  water  and  consequently  is  used  largely  for 
marine  work.  To  make  the  alloy,  melt  the  nickel  and  copper  to- 
gether under  borax,  then  add  2  ounces  of  aluminum  for  each 
100  pounds  of  alloy,  and  finally  add  the  zinc. 

Needle  metal,  so-called  on  account  of  its  fluidity. 

Pattern  Bronze. — The  name  implies  its  use  for  making  pat- 
terns.   It  files  well  and  casts  sharply. 

Turbine-Wheel  Mixture. — Inferior  in  strength  to  manganese- 
bronze,  but  less  liable  to  shrinkage  spots  and  porous  areas,  which 


170  ENGINEERING   CHEMISTRY 

are  particularly  objectionable  in  turbine  wheels.  The  metal 
should  be  poured  cool. 

Aluminum  Silver. — A  strong  white  metal  strong  in  copper.  As 
it  does  not  tarnish  in  the  air,  it  can  replace  steel  in  many  in- 
stances, e.  g.,  parts  of  typewriters,  adding  machines  and  similar 
contrivances.    The  metal  is  cast  and  remelted  before  use. 

Kayserzinn, — This  is  practically  Britannia  metal  under  a  new 
name.  It  appeared  in  1903,  and  was  imported  to  this  country 
from  Berlin. 

Tempered  Lead. — To  make  this  alloy,  melt  the  lead,  and  push 
the  sodium  in  small  pieces  into  the  molten  metal.  Ingots  of  the 
alloy  should  be  coated  with  paraffin  to  prevent  oxidation.  It 
is  much  harder  than  pure  lead. 

Soft  bearing  metal,  used  for  lining  car  boxes. 

Alkali-resisting  alloy,  sometimes  contains  as  much  as  10  per 
cent,  nickel.  Used  in  the  manufacture  of  machinery  which  comes 
in  contact  with  soap,  washing  soda,  bluing  or  starches.  Alloys 
containing  zinc,  tin,  lead,  aluminum,  antimony  or  silicon  are 
easily  corroded  by  caustic  alkali. 

White  Brass. — A  good  anti- friction  metal  having  double  the 
electrical  conductivity  of  Babbitt,  and  therefore  useful  in  elec- 
trical machinery. 

Analysis  of  Aluminum  Bronze. 
Take  i  gram  of  bronze  in  fine  turnings,  transfer  to  a  No.  3 
beaker  and  add  gradually  25  cc.  of  aqua  regia.  Evaporate  to 
dryness,  to  render  the  silica  insoluble,  take  up  with  25  cc.  hydro- 
chloric acid,  25  cc.  water,  warm,  filter,  and  wash  well.  The  resi- 
due is  dried,  ignited  and  weighed  as  SiO^,  and  calculated  to  Si. 
The  filtrate  from  the  silica  is  diluted  to  250  cc,  thoroughly  mixed 
and  100  cc.  transferred  to  a  No.  3  beaker  and  the  copper  pre- 
cipitated with  hydrogen  sulphide,  filtered,  washed  with  hydrogen 
sulphide  water,  the  cupric  sulphide  dissolved  in  nitric  acid,  and 
the  copper  determined  by  electrolysis.  The  filtrate  from  the 
cupric  sulphide  is  boiled  to  expel  hydrogen  sulphide,  a  few 
drops   of   nitric   acid   added,   the    solution   made   alkaline   with 


ENGINEEJRING   CHEMISTRY  I7I 

ammonia,  and  the  alumina  determined  as  AUOg,  and  calculated 
to  Al. 

Determination  of  Manganese  in  Manganese  Bronze.^ 

Dissolve  5  grams  of  drilling  in  nitric  acid  of  1.20  specific  grav- 
ity, using  a  large  beaker  to  avoid  frothing  over.  An  excess  of 
acid  must  be  avoided  as  it  interferes  with  the  precipitation  of  the 
copper  by  hydrogen  sulphide.  When  solution  is  complete,  trans- 
fer to  a  500  cc.  cylinder  without  filtering  out  the  precipitated 
stannic  oxide.  Make  up  to  300  cc.  and  pass  a  rapid  current  of 
hydrogen  sulphide  from  a  Kipp's  apparatus  until  the  supernatant 
liquid  is  colorless.  Decant  off  through  a  dry  filter,  180  cc.  cor- 
responding to  3  grams  of  sample,  and  boil  rapidly  down  to  about 
10  cc.  Transfer  to  a  small  beaker  and  add  25  cc.  of  strong 
nitric  acid.  Boil  down  one-half,  make  up  with  strong  nitric  acid, 
boil,  and  add  i  spoonful  of  potassium  chlorate.  Boil  10  minutes 
and  add  another  spoonful  of  potassium  chlorate.  Boil  until  free 
from  chlorine,  cool  in  water,  and  filter  on  asbestos,  using  filter 
pump.  Wash  with  strong  nitric  acid  through  which  a  stream  of 
air  has  been  passed.  When  free  from  iron,  wash  with  cold 
water  until  no  acid  remains.  Place  the  felt  and  precipitate  in  the 
same  beaker  and  dissolve  in  ferrous  sulphate,  using  5  cc.  at  a 
time.  Titrate  back  with  permanganate  until  a  pink  color  remains. 
Deduct  the  number  of  cubic  centimeters  used  in  titrating  back, 
from  the  number  of  equivalents  of  ferrous  sulphate  used,  and 
the  remainder  shows  the  manganese  in  the  amount  of  sample 
taken. 

Permanganate  Solution. — Dissolve  1.149  grams  of  potassium 
permanganate  in  i,ocx)  cc.  water;  i  cc.  equals  o.ooi  gram  manga- 
nese; check  by  dissolving  0.1425  gram  ammonio  ferrous  sulphate 
in  a  little  water  and  acidulating  with  sulphuric  acid.  This  should 
precipitate  10  milligrams  of  manganese.  If  not,  apply  factor  of 
correction. 

Ferrous  Sulphate  Solution. — A  solution  of  ferrous  sulphate  in 
2  per  cent,  sulphuric  acid  so  dilute  that  5  cc.  corresponds  to  10  cc. 
permanganate  solution.    This  is  best  made  by  trial  and  solution. 

^  Jesse  Jones:    /.  Am.   Chem.  Soc,    15,  414- 


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ENGINEERING    CHEMISTRY  I73 

Analysis  of  Ferro  Aluminum. 

Five  grams  of  the  ferro  aluminum  are  transferred  to  a  500  cc. 
beaker  and  dissolved  in  75  cc.  sulphuric  acid  (specific  gravity 
1.30),  then  evaporated  to  dryness.  The  residue  is  treated  with 
50  cc.  dilute  sulphuric  acid  diluted  to  300  cc.  and  mixed  well; 
100  cc.  of  the  solution  (=  1.666  grams)  are  filtered  off  into 
a  graduated  100  cc.  measure;  this  is  then  poured  into  a  250  cc. 
beaker;  about  5  grams  of  pure  iron  wire  are  now  added  and  the 
solution  boiled,  so  as  to  reduce  any  ferric  salt  formed ;  the  excess 
of  acid  is  carefully  neutralized  with  solution  of  sodium  carbonate 
and  the  mixture  gradually  poured  into  150  cc.  of  a  boiling  solu- 
tion containing  30  grams  of  potassium  hydroxide  and  60  grams 
of  potassium  cyanide;  the  mixture  of  potassium  cyanide  with 
iron  precipitated  as  hydroxide  is  diluted  up  to  500  cc.  in  a  gradu- 
ated measure,  and  300  cc.  (=  i  gram  of  sample)  filtered  off  into 
a  6-inch  evaporating  dish ;  200  cc.  of  a  standard  solution  of  am- 
monium nitrate  are  now  added  and  the  mixture  heaied  40  min- 
utes; filter  and  wash  the  precipitated  alumina  with  hot  water, 
redissolve  in  25  cc.  of  dilute  hydrochloric  acid,  dilute  to  2CX)  cc, 
neutralize  with  ammonium  hydroxide,  add  a  slight  excess,  boil, 
filter,  and  wash  with  hot  water,  dry  ignite,  and  weigh  as  Al^Og. 
The  weight  obtained  multiplied  by  0.534  X  100  ^  percentages  of 
aluminum.  This  amount  subtracted  from  100  per  cent,  gives  the 
percentage  of  iron.     (Phillips.) 

German  silver,  rosine,  aluminum  *'bourbounz,"  Guthrie's 
"eutectic"  and  arsenic  bronze  all  require  solutions  in  nitric  acid 
to  render  the  tin  insoluble,  which  is  then  separated  by  filtration 
from  the  other  components. 

The  determination  of  phosphorus  in  phosphor-tin  presents 
some  difficulty  on  account  of  the  insoluble  compound  which  phos- 
phoric acid  forms  with  stannic  oxide.    HempeP  states  as  follows : 

The  ordinary  way  of  analyzing  phosphide  of  tin  by  dissolving 
it  in  aqua  regia  and  precipitating  with  hydrogen  sulphide  is  not 
satisfactory,  as  a  considerable  quantity  of  phosphorus  is  thrown 
down  with  the  precipitated  sulphide  as  a  basic  phosphate  of  tin. 

^Ber.  d.  chem.  Ges.,  22,  2478;  /.  Anal.  Chem.,  4,  83. 


174  ENGINEERING   CHEMISTRY 

It  is  easily  analyzed  according  to  Wohler's  method,  by  treating 
with  chlorine,  the  chlorides  of  tin  and  phosphorus  formed  being 
collected  in  about  lo  cc.  of  concentrated  nitric  acid.  If  the  appa- 
ratus be  rinsed  with  a  solution  of  i  part  concentrated  nitric  acid 
and  2  parts  water,  no  trace  of  stannic  oxide  is  precipitated. 
The  phosphoric  acid  is  now  easily  precipitated  in  the  usual  way 
by  molybdic  acid. 

If  dilute  nitric  acid  is  taken,  a  part  of  the  phosphorus  separates 
with  the  stannic  oxide  and  the  result  will  be  too  low.  This  also 
applies  to  the  determination  of  phosphorus  in  phosphor  bronze. 

dualitative  Tests  of  Alloys  of  Lead,  Copper, 
Tin,  and  Antimony.^ 

For  lead,  dissolve  in  aqua  regia.  If  much  lead  be  present,  it 
will  separate  on  cooling  as  chloride;  if  only  a  small  amount  is 
present  it  will  be  detected  by  the  addition  of  4  volumes  of  95 
per  cent,  alcohol.^ 

For  tin,  dissolve  in  concentrated  hydrochloric  acid,  and  before 
the  portion  of  alloy  taken  is  completely  dissolved,  pour  off  the 
supernatant  solution,  cool  to  separate  lead  as  chloride,  add  4  vol- 
umes of  alcohol,  filter,  and  to  the  filtrate  add  a  slight  excess  of 
bromine  to  convert  stannous  to  stannic  chloride;  heat  to  expel 
free  bromine,  dilute,  and  pass  hydrogen  sulphide  gas,  when  if 
tin  is  present  it  will  be  obtained  as  yellow  stannic  sulphide. 

For  antimony,  treat  alloy  with  concentrated  hydrochloric  acid. 
Almost  all  the  antimony  is  left  undissolved.  Decant,  wash  the 
residue  with  water,  after  which  dissolve  in  hydrochloric  acid  with 
potassium  chlorate,  boil  to  expel  free  chlorine,  pass  hydrogen 
sulphide,  obtaining  a  precipitate  of  Sb^aSg,  if  antimony  is  present. 
If  copper  is  also  present,  it  will  be  precipitated  as  copper  sulphide 
and  may  obscure  the  color  of  the  antimonic  sulphide ;  if  so,  filter 
and  treat  the  precipitate  with  potassium  hydroxide  solution, 
which  will  dissolve  the  antimonic  sulphide.  Filter  and  acidify 
filtrate,  when  the  pure  color  of  antimonic  sulphide  will  be  ob- 
served if  antimony  is  present. 

^  Communicated  to  the  author  by  G.  W.  Thompson,  Chemist,  National  Lead  Co.,  N.Y. 
2  Consult,    The   Journal    of   Industrial    and    Engineering    Chemistry,    Vol.    I,    p.    520 
(Aug.,  1909). 


e:ngine;e;ring  che:mistry  175 

For  copper,  treat  the  alloy  with  dilute  nitric  acid  in  a  porce- 
lain dish  and  evaporate  to  dryness;  if  copper  is  present,  it  will 
show  as  a  green  ring  where  it  crystallizes  out  as  nitrate  on  the 
edge  of  the  residue. 

For  arsenic,  dissolve  alloy  in  hydrochloric  acid  with  addition 
of  potassium  chlorate  in  an  Erlenmeyer  flask,  boil  to  expel  chlo- 
rine, add  some  more  concentrated  hydrochloric  acid  and  2  ^rams 
of  sodium  thiosulphate,  connect  flask  with  a  condenser  and  distil, 
following  in  principle  the  method  first  proposed  by  Fischer. 
Arsenic,  if  present,  will  be  found  in  the  distillate  by  passing 
through  it  hydrogen  sulphide  gas. 

Cluantitative  Analysis  of  Alloys  Containing  Copper,  Lead, 
Antimony,  and  Tin.^ 

One  gram  of  the  finely  divided  alloy  is  dissolved  by  boiling  in 
from  70  to  100  cc.  of  the  following  solution,  in  a  covered  beaker. 

The  solution  is  made  by  dissolving  20  grams  of  potassium 
chloride  in  500  cc.  of  water,  adding  400  cc.  concentrated  hydro- 
chloric acid,  mixing,  and  then  adding  100  cc.  nitric  acid  of  1.40 
specific  gravity.  No  decomposition  between  hydrochloric  acid 
and  nitric  acid  takes  place  in  this  solution  in  the  cold.  If  com- 
plete solution  of  the  alloy  is  difficult  in  the  amount  of  solution 
taken,  more  is  added  as  required.  Continue  boiling  until  solution 
is  evaporated  to  about  50  cc.  Cool  by  placing  beaker  in  cold 
water  until  the  bulk  of  the  lead  has  crystallized  out  as  chloride, 
and  then  add  slowly  with  constant  stirring,  icx)  cc.  95  per  cent, 
alcohol.  Allow  to  stand  about  20  minutes,  filter  through  a 
9-centimeter  filter  paper  into  a  No.  4  beaker;  wash  by  decanta- 
tion  three  times  with  mixture  (4  to  i)  of  95  per  cent,  alcohol 
and  hydrochloric  acid,  concentrated,  and  wash  filter  paper  twice 
with  the  same  mixture. 

Wash  the  lead  chloride  on  the  paper  into  a  beaker,  and  wash 
filter  paper  several  times  with  hot  water,  allowing  washings  to 
flow  into  the  beaker  with  the  rest  of  the  chloride.  Finally  wash 
twice  with  solution  of  ammonium  acetate,  hot   (the  ammonium 

1  Method  of  G.  W.  Thompson. 


176  ENGINEERING   CHEMISTRY 

acetate  solution  is  made  by  taking  one  volume  of  ammonia  water 
(specific  gravity  0.900),  adding  to  it  i  volume  of  water  and  then 
acetic  acid  strong  until  the  reaction  is  slightly  acid  to  litmus), 
heat  until  the  lead  chloride  is  dissolved,  then  add  15  cc.  of  a 
saturated  solution  of  potassium  bichromate,  and  warm  until  pre- 
cipitate is  of  good  orange  color.  Filter  on  weighed  gooch  cru- 
cible, wash  with  water,  alcohol,  and  ether,  dry  at  110°  C,  and 
weigh. 

Evaporate  filtrate  from  lead  chloride  by  heating  on  a  hot  plate 
and  finally  to  dryness  on  water-bath;  add  10  cc.  solution  potas- 
sium hydroxide  (i  gram  to  5  cc.)  and  after  a  few  minutes  20  cc. 
hydrogen  peroxide;  heat  on  water-bath  for  20  minutes,  add 
10  grams  ammonium  oxalate,  10  grams  oxalic  acid,  and  200  cc.  of 
water.  Heat  to  boiling,  pass  hydrogen  sulphide  with  solution 
near  boiling  for  45  minutes;  filter  at  once  and  wash  precipitate 
with  hot  water.  Boil  filtrate  to  expel  hydrogen  sulphide,  con- 
centrate if  necessary,  and  electrolyze  over  night,  using  a  current 
of  about  0.5  ampere.  Usually  by  morning  the  solution  will  have 
become  alkaline,  in  which  case  it  may  be  taken  for  granted  that 
the  tin  is  all  precipitated  on  the  cylinder.  The  cylinder  is  re- 
moved, washed  twice  with  water  and  then  with  95  per  cent, 
alcohol,  dried,  and  weighed.  The  precipitate  of  antimony  and 
copper  sulphides  on  paper  is  washed  back  into  the  beaker  with 
the  least  amount  of  water  possible,  and  treated  with  10  cc.  potas- 
sium hydroxide  solution  (i  :  5),  heated  on  a  water-bath  until  un- 
dissolved matter  is  distinctly  black;  it  is  then  filtered  through  the 
same  paper  it  was  washed  from,  into  a  12-ounce  Erlenmeyer 
flask,  washed,  etc.  On  the  filter  the  copper  is  obtained  as  sulphide 
with  a  small  amount  of  lead  which  failed  of  precipitation  as 
chloride.  If  it  is  desired  to  determine  this  lead,  it  can  be  done  by 
separation  from  the  copper  as  usual ;  if  not,  dry  and  ignite  pre- 
cipitate in  a  small  casserole,  dissolve  in  nitric  acid,  boil  to  expel 
nitrogen  dioxide,  neutralize  with  sodium  carbonate,  add  a  few 
drops  of  ammonia,  and  determine  volumetrically  with  potassium 
cyanide  standardized  against  pure  copper.  The  solution  of  anti- 
mony sulphide  in  potassium  hydroxide  should  not  amount  to  over 


ENGINEERING    CHEMISTRY  1 77 

40  cc.  Add  I  gram  potassium  chlorate,  50  cc.  concentrated  hy- 
drochloric acid,  boil  until  solution  is  colorless  and  free  chlorine 
is  driven  off;  filter  through  mineral  wool ;  if  sulphur  has  separated 
into  a  similar  flask,  wash  out  original  with  concentrated  hydro- 
chloric acid,  cool,  add  i  gram  of  potassium  iodide,  i  cc.  carbon 
disulphide,  and  titrate  tor  antimony  with  tenth-normal  sodium 
thiosulphate,  i  cc.  of  which  equals  0.0060  gram  antimony.  This 
systematic  method  assumes  the  absence  of  other  metals  than  lead, 
tin,  antimony,  and  copper.  For  the  determination  of  other  metals 
we  offer  the  following  suggestions :  If  arsenic  is  present  it  will 
be  separated  with  the  antimony  and  will  liberate  iodine,  as  does 
antimony.  One  cc.  of  tenth-normal  thiosulphate  equals  0.00375 
gram  of  arsenic.  Arsenic  is  preferably  determined  on  a  separate 
portion  by  dissolving  in  hydrochloric  acid  and  potassium  chlorate, 
boiling  to  expel  free  chlorine,  and  distilling  after  the  addition  of 
sodium  thiosulphate  as  a  reducing  agent,  passing  hydrogen  sul- 
phide through  the  distillate  and  weighing  as  As^Sg,  or  dissolving 
in  potassium  hydroxide  and  determining  volumetrically  as  in  the 
case  of  antimony. 

Bismuth^  and  cadmium  sulphides  would  remain  with  copper 
after  treatment  with  potassium  hydroxide — this  renders  this 
method  very  suitable  for  fusible  metals.  Zinc  would  interfere 
with  this  method,  but  as  zinc  does  not  alloy  with  lead,  we  will 
not  speak  of  it  further.  Nickel  and  cobalt  alloy  but  slightly  with 
tin,  and  if  present,  should  be  sought  for  both  in  the  precipitate 
left  by  potassium  hydroxide  and  in  the  tin  precipitated  on  a 
cylinder.  Iron  will  also  be  precipitated  with  tin  if  present  in  an 
oxalic  acid  solution.  Phosphorus  is  best  determined  by  Dudley's 
method. - 

In  alloys  containing  only  lead  and  tin,  with  the  tin  under  20 
per  cent.,  the  two  constituents  can  best  be  determined  by  treat- 
ment with  dilute  nitric  acid  in  a  pocelain  dish,  evaporating  to 
dryness  on  a  water-bath,  etc.,  and  determining  lead  as  chromate 
and  tin  as  stannic  oxide.     In  samples  free  from  iron  and  copper, 

^  Consult,  "Note  on  the  solubility  of  bismuth  sulphide   in  sodium  sulphide,   etc.," 
Stillman,  J.  Atner.   Chem.  Soc,  Vol.    i8,  Aug.,   1896. 
2  Am.  Eng.  and  R.  R.  /.,  8,  128  (1914)- 

12 


lyS  EJNGIN^ISRING   CHEMISTRY 

antimony  may  be  determined  directly  by  solution  in  hydrochloric 
acid  and  potassium  chlorate,  boiling  to  expel  chlorine,  and  titra- 
ting as  with  pure  antimony.  Antimony  in  solders  may  be  deter- 
mined very  accurately  by  dissolving  in  hydrochloric  acid  without 
access  of  air  and  filtering  out  the  undissolved  antimony  on  a 
weighed  gooch  crucible.  I  have  not  found  that  a  weighable 
amount  of  antimony  was  lost  as  stibine  by  this  treatment.  In 
the  analysis  of  alloys  of  lead  and  tin,  Richards'  scales  which  are 
accurate  within  i  per  cent.,  may  be  used.  In  the  examination  of 
the  various  classes  of  alloys  described  at  the  beginning  of  this 
paper,  various  steps  in  their  analysis  may  be  left  out  with  the 
absence  of  the  respective  metals. 

Rapid  Method  for  Determination  of  Sb,  in  Presence  of  Sn,  and  Pb. 

Dissolve  sample  i  to  5  grams  according  as  content  is  o.i  to  i 
per  cent,  or  over  with  chemically  pure  hydrochloric  acid  in  6  oz. 
flask.  Pour  off  supernatant  solution  carefully.  Dissolve  Sb 
residue  (washing  not  necessary)  in  dilute  HCl  and  small  amount 
of  chlorate  of  potash.  Boil,  cool  and  titrate  with  thiosulphate  of 
sodium  potassium  iodide  and  CS^  indicator.  Shake  up  well  with 
CS;2-    Color  reaction  is  very  accurate  (Louis  Ruprect). 

A  Method  for  the  Rapid  Quantitative  Analysis  of  Bronze  and  Brass.^ 
(Pb,  Cu,  Sn,  Sb,  Fe,  and  Zn.) 

Introduction. 
The  method  of  analysis  reported  in  this  paper  is  the  outgrowth 
of  an  investigation  that  was  undertaken  as  the  result  of  a  request 
made  to  one  of  us  sometime  ago  to  take  charge  of  some  "control" 
work  for  a  large  company  manufacturing  bronze  metal  in  various 
forms.  Most  of  the  metal  is  sold  on  specification.  The  alloy 
supplied  by  this  firm  varies  in  composition  as  follows :  Cu,  65  to 
69  per  cent. ;  Pb,  25  to  30  per  cent;  Sn,  5  to  6  per  cent. ;  Fe,  o.i 
to  0.3  per  cent.;  Zn,  1.5  to  3  per  cent.  The  requirements  were 
that  the  analysis  be  accurate  to  0.2  per  cent,  and  that  the  time 
consumed  in  making  the  complete  analysis  should  not  exceed 
I  hour,  preferably  45  minutes. 

^  Presented    at   the   49th    meeting   of   the   American    Chemical    Society,    Cincinnati, 
April  6-10,    19 14,  by  Richard  Edwin  Lee,  John  P.  Trickey  and  Walter  H.   Fegely. 


e:ngine:e:ring  chemistry  179 

Part  I. — Method  of  Analysis. 

De:termination  of  Lead. 

Procedure. — To  0.5  gram  of  the  alloy  in  a  300  cc.  Erlenmeyer 
flask,  add  12  cc.  of  water  containing  4  grams  of  tartaric  acid,  and 
then  4  cc.  of  concentrated  HNO3.  Place  on  a  hot  plate  to  dis- 
solve the  alloy  quickly.  (The  solution  should  be  perfectly  clear; 
if  not,  reject  it  and  repeat  the  procedure.)  Remove  the  solution 
from  the  hot  plate,  allow  to  cool  from  i  to  2  minutes,  add  10  cc. 
concentrated  11^804,  and  then  heat  on  hot  plate  until  all  nitrous 
fumes  are  expelled.  {Caution:  Care  must  be  exercised  not  to 
carry  the  procedure  beyond  this  stage  or  the  tartaric  acid  will  be 
decomposed.)  Dilute  with  100  cc.  of  cold  water,  add  75  cc.  of 
ethyl  alcohol,  shake,  allow  to  stand  for  2  or  3  minutes,  filter 
through  a  weighed  gooch  crucible,  wash  with  water  to  which  a 
little  H,2S04  has  been  added,  until  the  precipitate  is  white  and 
then  wash  out  acid  with  alcohol.  Reject  the  filtrate.  Dry  the 
precipitate  in  crucible  on  hot  plate,  and  then  heat  to  dull  redness 
with  the  Bunsen  burner  for  a  few  minutes.  Cool  and  weigh  as 
PbSO^. 

Wt.  PbSO^  X  0.683  =  wt.  Pb 

Notes. 

1.  In  order  to  prevent  occlusion  and  adsorption  of  the  Cu  salts  by 
the  lead  sulphate  precipitate,  it  was  found  necessary  to  make  the  solution 
from  which  the  lead  precipitate  is  separated  by  filtration  relatively  large. 
The  solution  of  the  lead  sulphate  is  prevented  by  the  addition  of  alcohol. 

2.  In  case  the  alloy  contains  a  small  percentage  of  lead,  it  is  advisable, 
of  course,  to  use  a  relatively  large  amount  of  the  sample.  If  this  is  done, 
the  quantities  of  the  reagents  employed,  including  water  and  alcohol, 
should  be  increased  proportionately.  The  reasons  for  this  procedure  are 
obvious.  In  the  first  place,  unless  the  volume  of  the  solution  is  made 
larger  the  concentration  of  the  Cu  and  other  metals  present  becomes  very 
large  owing  to  the  use  of  larger  amounts  of  sample.  This  will  increase 
the  error  due  to  occlusion  and  adsorption  as  mentioned  in  Note  i.  In 
the  second  place,  in  order  to  preserve  the  proper  concentration  of  sulphate 
ions  for  the  complete  precipitation  of  Pb  in  this  larger  volume  of  solu- 
tion it  is  necessary  to  use  larger  amounts  of  the  reagent,  sulphuric  acid. 

DETERMINATION    OF    CoPPER. 

Procedure. — Place  0.5  gram  of  the  alloy  in  a  406  cc.  beaker. 


i8o  e;ngine;e;ring  chemistry 

add  5  to  lo  cc.  of  dilute  HNO3  (1:1),  cover  beaker  with  a 
watch  glass  until  violent  action  ceases,  then  remove  watch  glass 
and  evaporate  on  hot  plate  to  sirupy  consistency.  Dilute  to 
about  200  cc.  and  add  KOH  solution  until  a  small  precipitate  of 
copper  hydroxide  persists  after  thorough  stirring.  Now  add 
acetic  acid  until  the  copper  precipitate  is  completely  dissolved, 
then  add  a  small  excess  of  the  acid.  Cool  the  mixture  to  tap- 
water  temperature,  then  add  40  cc.  of  the  KI  solution  (100  grams 
to  I  liter)  and  5  cc.  of  starch  solution,  and  titrate  immediately 
with  standard  Na^sSoOg  solution  until  the  blue  color  disappears. 

Notes. 

1.  It  has  been  pointed  out  by  Walker  and  Whitman'  that  the  results 
obtained  by  following  Low's  iodide  method"  are  uniformly  a  little  low. 
They  add  "This  error  is  not  due  to  the  method  which  gives  exceedingly 
accurate  results,  but  to  the  fact  that  nearly  6  per  cent,  of  the  copper  is 
not  precipitated  as  cuprous  oxide.  This  loss  is  uniform,  for  if  we  add 
6  per  cent,  of  the  copper  determined  the  result  will  be  the  per  cent,  of 
the  copper  in  the  alloys."  This  is  undoubtedly  true.  Their  further  state- 
ments, however,  that  when  an  alloy  containing  5  per  cent,  of  copper  is 
decomposed  by  nitric  acid,  evaporated  to  dryness,  taken  up  with  nitric 
acid  and  filtered,  the  error  in  determining  the  copper  in  the  filtrate  will 
frequently  be  0.5  to  0.7  per  cent.,  cannot  be  confirmed  by  our  experience. 
By  following  the  proposed  method  of  standardization  and  analysis,  which 
is  essentially  Low's  method,  we  have  been  able  to  check  within  o.i  per  cent, 
repeatedly. 

2.  Provision  has  not  been  made  in  the  method  as  formulated  for  the 
separation  of  copper  from  any  other  metals,  yet  care  must  be  exercised 
to  exclude  from  the  solution  prepared  for  titration  any  substances  which 
will  either  liberate  or  absorb  iodine.  Therefore,  free  CI,  free  Br,  nitrous 
oxides,  ferric  ions,  and  As  and  Sb  in  the  "ous"  condition  must  be  absent. 

Ferric  ions  may  be  removed  by  adding  ammonium  fluoride,  which 
interacts  with  the  former  to  produce  ferric  fluoride.  This  latter  substance 
which  is  only  slightly  ionized  has  little  or  no  oxidizing  power  and,  there- 
fore, cannot  liberate  iodine  under  the  existing  conditions. 

The  trivalent  arsenic  and  antimony,  if  present,  must  be  oxidized  to 
the  pentavalent  condition  by  the  addition  of  bromine.  Excess  of  bromine 
must  be  removed  by  boiling  the  solution  before  titrating. 

No  other  elements  interfere  with  the  procedure. 

3.  Pb,  Bi,  and  Cd,  if  present,  interact  with  the  KI  and  form  the 
corresponding  yellow  insoluble  iodides.     This  causes  no  trouble,  however ; 

'^Journal  of  the  Industrial  and  Engineering  Chemistry,  1,  (1909),  519. 
^Jour.  Am.  Chem.Soc,  24,  (1902),  1082. 


Engine:ering  che:mistry  i8i 

in  fact  many  chemists  regard  the  presence  of  one  or  more  of  these  metals 
as  a  distinct  advantage  as  the  presence  of  the  yellow  precipitate  assists  the 
operator  in  securing  uniform  end  points.  In  this  laboratory  it  is  cus- 
tomary to  add  a  few  cubic  centimeters  of  a  solution  of  lead  acetate  to 
the  solution  to  be  titrated  if  it  is  known  that  Pb  is  not  present. 

4.  In  order  that  the  liberated  iodine  may  be  held  in  solution  it  is 
necessary  to  use  rather  large  excess  of  KI.  This  procedure  increases  the 
speed  of  the  reaction. 

5.  The  presence  of  an  excess  of  inorganic  acid  interferes-  with  the 
procedure.  It  should  be  remembered,  however,  that  unless  the  solution 
contains  a  sufficient  excess  of  acetic  acid  the  end  point  will  not  be  sharp, 

6.  The  solution  should  always  be  cooled  to  tap  water  temperature 
just  before  the  KI  solution  is  added. 

7.  It  should  be  remembered  that  the  Sn  present  will  make  an  insol- 
uble residue  in  the  solution  prepared  for  titration. 

Determination  of  Tin   (and  Sb). 

Procedure. — Weigh  0.5  gram  of  the  alloy  into  a  400  cc.  beaker, 
add  5  to  10  cc.  of  dilute  HNO3  (1:1),  cover  with  a  watch 
glass  until  violent  action  ceases,  then  remove  cover  and  evaporate 
to  a  paste  on  hot  plate.  Add  15  cc.  of  dilute  HNO3,  boil  for 
several  minutes  and  dilute  to  about  200  cc.  Boil  for  a  few  min- 
utes, filter  through  a  weighed  gooch  crucible,  wash  with  hot 
nitric  acid  wash,  and  then  with  hot  water.  Pour  the  filtrate  into 
a  500  cc.  beaker  and  reserve  for  check  determination  of  copper. 
Dry  the  crucible  and  contents  on  hot  plate  and  then  ignite  at  red 
heat  for  10  minutes.  The  ignited  residue  consists  of  SnO,2  and 
any  Sb  (as  Sb204)  which  may  have  been  present  in  the  alloy. 
Wt.  SnOj  (and  Sb^OJ    X  0.788  =  wt.  Sn   (and  Sb) 

Notes. 

1.  The  results  obtained  by  this  method  are  usually  a  little  high,  owing 
to  the  fact  that  the  precipitate  frequently  contains  traces  of  the  oxides 
of  Cu,  Sb,  and  Pb.  However,  the  digestion  of  the  dried  residue  in  dilute 
nitric  acid  and  the  final  separation  of  the  precipitate  from  a  large  volume 
•of  solution,  tend  to  reduce  errors  from  this  source.  The  precipitate  will 
also  contain  any  phosphorus  that  is  present  in  the  sample. 

2.  Much  time  and  energy  were  consumed  in  an  effort  to  obtain  a 
volumetric  method  for  determining  tin  in  a  separate  portion  of  the  alloy. 
One  of  the  most  attractive  volumetric  methods  for  making  this  deter- 
mination   is    Walker    and    Whitman's    modification^    of    Low's    idimetric 

^Journal  of  the  Industrial  and  Engineering  Chemistry,  1,  (1909),  519. 


i82  e:ngine:e:ring  che;mistry 

method.  Our  efforts,  however,  to  adapt  It  to  our  scheme  of  analysis  were 
without  success.  The  chief  obstacle  to  its  application  to  the  rapid  analysis 
of  bronze  is  the  presence  of  a  relatively  large  percentage  of  Cu  in  the 
alloy.  The  method,  however,  was  found  to  give  excellent  results  when 
used  in  making  analyses  of  Babbitt  metal  if  the  percentage  of  Cu  in  the 
alloy  was  small;  but  if  the  percentage  of  Cu  was  large  the  results  came 
high,  ow.ing  to  the  fact  that  during  the  reduction  of  the  Sn  the  Cu  was 
reduced  to  cuprous  chloride  which  takes  up  a  portion  of  the  iodine  when 
the  solution  is  finally  titrated.  Our  results  in  regard  to  the  errors  intro 
duced  by  the  titration  of  Sn  in  the  presence  of  Cu  agree  with  those 
obtained  by  Ibbotson  and  Aitchison.^ 

(Check  Dete;rmination  of  Copper.) 
Procedure. — Cool  the  filtrate  from  the  Sn  determination,  add 
KOH  solution  until  a  small  precipitate  of  copper  hydroxide  per- 
sists after  thorough  stirring.  Add  acetic  acid  until  the  copper 
precipitate  is  completely  dissolved,  then  add  a  small  excess  of 
the  acid.  Follow  directions  as  given  under  Determination  of 
Copper. 

Determination  of  Antimony. 

Procedure. — Weigh  out  0.5  gram  of  the  fine  drillings  of  the 
alloy  into  a  300  cc.  Kjeldahl  flask,  add  25  cc.  of  concentrated 
sulphuric  acid  and  heat  over  the  bare  flame  of  a  Bunsen  burner. 
Keep  the  acid  at  its  boiling  point  until  the  solution  is  clear  or  the 
residue  is  white.  Cool,  add  100  cc.  of  water,  boil  for  several 
minutes  and  transfer  the  contents  of  the  flask  to  a  400  cc.  beaker. 
Dilute  to  200  cc,  heat  to  70°  C.  (158°  F.)  and  titrate  with  a 
standard  KMn04  solution.  The  permanganate  solution  should 
be  added  rapidly  until  the  permanganate  color  persists,  then  add 
several  cubic  centimeters  in  excess.  Stir  the  solution  vigorously, 
and  then  titrate  with  a  standard  solution  of  ferrous  ammonium 
sulphate  until  the  pink  color  just  disappears. 

Notes. 

I.  Although  antimony  is  not  found  in  the  majority  of  bronzes  and 
brasses  it  frequently  occurs  alloyed  with  variable  percentages  of  lead,  tin, 
copper  and  iron.  Therefore,  in  order  to  make  the  present  scheme  of 
analysis  as  wide  as  possible  in  its  application  and  thereby  increase  its 
usefulness,  it  was  deemed  advisable  to  incorporate  a  method  for  the  rapid 
determination  of  Sb. 

1  Chem.  News,  107  (1913),  109;  also  C.  A.,  7  (1913),  2005;  8  (1914),  476. 


ENGINEERING   CHEMISTRY  183 

2.  The  method  is  at  once  recognized  as  a  modification  of  Low's  well 
known  method/  The  chief  difficulty  we  experienced  in  fitting  it  to  our 
scheme  of  analysis  was  the  matter  of  securing  Sb  in  a  suitable  condition 
in  sulphuric  acid  solution.  Alloys  containing  a  high  percentage  of  copper 
resist  solution  by  the  usual  procedure.  Nitric  acid  is  ehminated  as  a 
solvent  because  of  its  oxidizing  action ;  and  HCl  and  KCIO3  are  ineffective 
unless  the  treatment  is  greatly  prolonged.  Finally,  the  not  entirely  satis- 
factory method  of  decomposing  the  alloy  in  concentrated  sulphuric  acid 
in  a  Kjeldahl  flask  exposed  to  the  bare  flame  of  a  Bunsen  burner  was 
adopted.  Complete  decomposition  is  usually  effected  in  10  to  20  minutes, 
after  which  the  determination  may  be  readily  finished  in  10  minutes. 

After  one  or  two  trials,  it  will  probably  be  found  that  the  blue  color 
imparted  to  the  solution  by  the  presence  of  the  copper  does  not  hinder 
the  determination  of  the  exact  end  point  when  the  permanganate  is  added. 

3.  Demorest  has  pointed  out  in  an  excellent  paper"  that  it  is  necessary 
to  employ  a  large  excess  of  potassium  permanganate  to  complete  the 
oxidation  of  the  Sb.  It  is  not  best  to  have  HCl  present  when  the  anti- 
mony is  titrated  as  the  end  point  is  made  very  transient  by  its  presence. 

Determination  of  Iron  and  Zinc. 

Procedure. — To  0.5  gram  of  the  alloy  in  a  400  cc.  beaker  add 
sufficient  dilute  HNO3  (1:1)  to  dissolve  the  sample.  Heat  on 
hot  plate  until  the  alloy  is  thoroughly  decomposed,  then  evaporate 
the  solution  just  to  dryness.  Add  10  cc.  of  concentrated  HCl  and 
100  cc.  of  water,  heat  to  about  70°  C.  and  pass  H^S  through 
the  mixture  until  all  the  Pb,  Cu,  Sn,  and  Sb  (Cd,  etc.)  are  pre- 
cipitated. Filter,  using  a  Buchner  funnel  with  an  asbestos  mat, 
wash  the  precipitate  with  water.  The  filtrate  which  contains  the 
iron  and  zinc  should  be  transferred  to  a  500  cc.  beaker. 

Note;. 

A  drop  of  this  filtrate  should  be  transferred  to  a  spot  plate  and  tested 
with  a  drop  of  potassium  ferrocyanide  for  the  presence  of  Cu  and  Fe 
which  are  interfering  substances  and  if  present  in  weighable  quantities 
they  should  be  removed.  If  Cu  is  present,  which  will  be  indicated  by 
the  presence  of  red  coloration,  treat  the  filtrate  again  with  hydrogen 
sulphide  and  filter ;  if  Fe  is  present,  which  will  be  indicated  by  the  appear- 
ance of  a  blue  coloration,  proceed  as  directed  under  (2),  Iron  and  Zinc. 

I,  Zinc,  if  Fe  is  Absent. — Dilute  the  filtrate  to  200  cc,  heat  to 
70°  C.  and  titrate  with  standard  potassium  ferrocyanide,  using 

^Journal  of  the  Industrial  and  Engineering  Chemistry,  5  (1913),  842. 
2  Ibid..  5  (1913),  842. 


184  KNGINEKRING   CHEJMISTRY 

ferric  chloride  or  uranyl  nitrate  as  an  indicator.  The  titration 
should  be  performed  slowly  and  with  constant  stirring  in  order 
to  obtain  the  most  satisfactory  results.  Continue  to  kdd  the 
ferrocyanide  until  a  drop  of  the  solution  in  the  beaker  shows  a 
bluish  green  tinge  (brown  tinge  when  uranyl  nitrate  is  used  as 
an  indicator)  when  tested  on  a  white  porcelain  plate  with  a  drop 
of  ferric  chloride  after  standing  a  few  seconds.  The  quantity 
of  the  standard  solution  which  is  acquired  to  produce  a  good  end 
point  in  the  blank  determination  made  at  the  time  of  standard- 
izing the  solution,  must  be  subtracted  from  the  amount  of 
standard  used  in  making  the  determination. 

Notes. 

1.  Correction  for  Blank. — As  the  indicators  are  not  very  sensitive 
under  the  imposed  conditions,  it  is  necessary  to  determine  the  excess  of 
standard  solution  required  to  effect  the  color  change  of  the  indicator  used. 
A  "blank"  must  be  run,  therefore,  using  the  same  quantities  of  reagents 
under  corresponding  conditions  of  volume,  temperature  and  acidity. 

2.  If  the  solution  turns  blue  during  the  titration,  it  is  an  indication 
of  the  presence  of  small  quantities  of  iron. 

2.  Iron  and  Zinc. — Add  2  cc.  of  concentrated  HNO3  to  the 
filtrate  to  oxidize  the  Fe,  heat  to  boiling  add  25  cc.  5/N  NH^Cl 
and  then  NH4OH  until  the  odor  of  the  reagent  barely  persists 
after  boiling  the  mixture  for  i  minute.  Filter  off  the  Fe(OH)3 
and  ignite.     Weigh  as  Fe^O^. 

Notes. 

1.  Zinc  is  completely  precipitated  from  HCl  solutions  by  potassium 
ferrocyanide  as  white  zinc  ferrocyanide.  Such  metals  as  Pb,  Cu,  Sn,  Fe 
and  Mn  are  also  precipitated  by  this  reagent,  and  therefore  must  be 
removed  before  the  Zn  is  titrated. 

2.  The  acid  solution  must  not  contain  free  CI,  free  Br  or  the  oxides 
of  chlorine  as  these  substances  decompose  ferrocyanide. 

3.  Care  must  be  taken  to  conduct  the  standardization  as  well  as  all 
determinations  under  corresponding  conditions  with  particular  reference 
to  volume,  temperature,  acidity,  amount  of  ammonium  salts  and  the  rate 
of  titration.  Furthermore,  it  is  imperative  that  the  titration  be  conducted 
slowly  and  with  constant  stirring  of  the  solution.  If  this  precaution  is 
no  observed  the  end  point  will  be  reached  apparently  before  all  the  zinc 
is  precipitated. 


DNGINEERING   CHE:mISTRY  185 

Specifications  for  Inspection  of  Material,  Copper, 
Brass  and  Bronze. 

Used  in  the  construction  of  machinery  coming  under  the  cognizance 
of  the  Bureau  of  Steam  Engineering,  Navy  Department,  U.  S.   (1908). 

Specifications  for  Miscellaneous  Brass  Castings. 

[88-10-2  Mixture.] 
For  ali.  Purposes  for  which  no  other  Aeloy  is  Specified. 

The  inspection  of  these  castings  shall  conform  to  the  "General 
instructions  for  the  inspection  of  copper,  brass,  and  bronze  material  com- 
ing under  the  cognizance  of  the  Bureau  of  Steam  Engineering." 

The  composition  must  be  made  of  materials  of  the  purest  commercial 
quality. 

The  naval  inspector  will  take  drillings  for  chemical  analyses. 

The  analysis  must  show  that  the  metal  contains  not  less  than  87 
per  cent,  nor  more  than  89  per  cent,  copper ;  not  less  than  9  per  cent, 
nor  more  than  11  per  cent,  tin  and  the  remainder  zinc. 

Chemical  Analysis. 

Government  Analysis. — Drillings  for  analysis  must  be  fine,  clean,  dry, 
and  free  from  scale.  The  inspector  may  take  them  from  any  test  piece, 
or  from  any  part  of  the  material,  provided  in  this*  last  case  that  by  so 
doing  the  material  will  not  be  rendered  unfit  for  use.  Unless  otherwise 
requested,  the  chemist  will  make  determinations  of  those  elements  only 
which  are  limited  by  the  specifications. 

Specifications  for  Seamless  Brass  Pipe,  Iron  Pipe  Sizes,  Mads  to 
Correspond  with  Iron  Pipe  and  to  Fit  Iron  Pipe  Fittings. 

Material. — Pipe  shall  be  made  of  material  of  purest  commercial 
quality,  compounded  from  60  to  70  per  cent,  of  pure  copper  and  from 
40  to  30  per  cent,  of  pure  zinc,  and  not  more  than  0.5  of  i  per  cent,  of 
lead,  the  manufacturer  being  allowed  this  variation  of  composition  in 
order  to  get  the  material  best  suited  for  the  purpose  for  which  it  is 
intended.    The  naval  inspector  will  take  drillings  for  chemical  analyses. 

The  pipe  will  be  inspected  for  surface  defects  and  it  must  be  free 
from  cracks,  seams,  and  defects  generally. 

Each  pipe  must  withstand  an  internal  hydraulic  pressure  which  will 
subject  the  metal  to  a  stress  of  7,000  pounds  per  square  inch  without 
showing  weakness  or  defects,  in  accordance  with  the  formula  for  thin 
hollow  cylinders  under  tension  where 


i86  e:nginekring  chemistry 

p  =  safe  internal  pressure ; 

d  =  inside  diameter  of  pipe  in  inches ; 

J  =  safe  tensile  strength  of  material  =  7,000  pounds  per  square 

inch; 
t  =  thickness  of  pipe  in  inches ; 
but  no  pipe  will  be  tested  beyond  1,000  pounds  per  square  inch  per  gauge, 
unless  specially  directed. 

All  pipe,  unless  ordered  "hard,"  is  to  be  annealed  sufficiently  to  pre- 
vent fire  cracking  and  to  stand  the  physical  tests.  "Brass  pipe  for  radia- 
tors for  heating  system,  and  similar  purposes,  to  be  semi-annealed,  and  to 
stand  bending  180°  around  a  diameter  of  i  ^/le  inches." 

When  the  pipe  is  finished  (ready  for  shipment),  the  naval  inspector 
will  subject  i  per  cent,  of  the  lot,  taken  at  random,  to  the  following 
physical  tests : 

(a)  The  end  of  each  test  pipe  must  stand  being  flattened  by  ham- 
mering until  the  sides  are  brought  parallel,  with  a  curve  on  the  inside  at 
the  ends  not  greater  in  diameter  than  twice  the  thickness  of  the  metal  in 
the  pipe,  without  showing  cracks  or  flaws. 

(b)  Each  test  pipe  shall  have  a  piece  3  inches  long  cut  from  it,  which 
piece  when  split  must  stand  opening  out  flat  without  showing  cracks  or 
flaws. 

(c)  Each  test  pipe  must  stand  threading  in  a  satisfactory  manner 
with  the  usual  thread  for  the  size  of  the  pipe.  When  the  pipe  is  ordered 
"hard,"  the  (a)  and  (b)  tests  shall  be  made  on  annealed  test  specimens. 
These  (a),  (b),  (c)  tests  shall  be  made  on  each  of  the  test  pipes,  and 
the  test  specimens  shall  be  furnished  at  the  contractor's  expense.  If  any 
of  these  pipes  selected  for  tests  fail,  the  naval  inspector  will  select  two 
extra  pipes  from  the  same  lot  and  put  them  through  the  same  test  as  the 
pipe  that  failed,  and  both  of  these  pipes  must  be  found  satisfactory  in 
order  that  the  lot  may  be  passed.  The  failure  to  pass  satisfactorily  any 
one  of  the  tests  marked  (a),  (b),  (c)  will  reject  the  lot. 

All  pipe  shall  be  up  to  the  gauge  ordered.  Each  large  single  pipe,  or 
bundle  of  small  pipes,  must  be  marked  with  the  name  of  the  vessel  for 
which  it  is  intended,  or  with  the  number  of  the  order.  The  standard 
weight  for  seamless  drawn  brass  pipe  will  be  0.3  pound  per  cubic  inch 
of  material,  but  a  tolerance  not  to  exceed  5  per  cent,  over  weight  will  be 
allowed. 

Specifications  for  Seamless  Pipe  of  ''Benedict  Nickel"  or  Other 
Equivalent  Metal. 

Material — They  shall  be  made  of  material  of  purest  commercial 
quality  compounded  from  at  least  15  per  cent,  nickel  and  the  remaining 


ENGINEEJRING   CHEMISTRY  187 

metal  pure  copper.  The  naval  inspector  will  take  drillings  for  chemical 
analyses. 

The  pipes  will  be  inspected  for  surface  defects.  They  must  be  free 
from  cracks,  seams,  and  injurious  defects  generally. 

Each  pipe  shall  be  subjected  to  an  internal  water  pressure  equivalent 
to  a  tensile  stress  of  14,000  pounds  per  square  inch  without  showing  weak- 
ness or  defects,  in  accordance  with  the  formula  for  thin  hollow  cylinders 
under  tension  where 

p  =  safe  internal  pressure ; 

d  =  inside  diameter  of  pipe  in  inches ; 

j-  izz  safe  tensile  strength  of  material  =  14,000  pounds  per  square 
inch; 

t  =  thickness  of  pipe  in  inches ; 
but  no  pipe  shall  be  tested  beyond  2,000  pounds  per  square  inch  per  gauge, 
unless  specially  directed. 

When  the  pipe  is  finished  (ready  for  shipment),  the  naval  inspector 
will  subject  i  per  cent,  of  the  pipe,  taken  at  random,  to  the  following 
physical  tests : 

(a)  Test  specimens  selected  from  these  shall  not  show  less  than 
65,000  pounds  tensile  strength  per  square  inch. 

(b)  The  end  of  each  test  pipe  must  stand  being  flattened  by  ham- 
mering until  the  sides  are  brought  parallel,  with  a  curve  on  the  inside  at 
the  ends  not  greater  in  diameter  than  the  thickness  of  the  metal  in  the 
pipe,  without  showing  cracks  or  flaws. 

(c)  Each  test  pipe  shall  have  a  piece  3  inches  long  cut  from  it,  which 
piece  when  split  must  stand  opening  out  flat  without  showing  cracks  or 
flaws. 

(d)  Each  test  pipe  must  stand  threading  in  a  satisfactory  manner 
with  the  usual  thread  for  the  size  of  the  pipe. 

(e)  The  end  of  a  pipe,  cold,  must  stand  having  a  taper  pin,  taper 
i^  inches  to  the  foot,  driven  into  it  until  the  end  of  the  piece  stretches 
to  i^  times  the  original  diameter  without  showing  cracks  or  flaws. 

(/)  A  piece  of  the  pipe  one  diameter  long  must  stand  crushing  in 
the  direction  of  its  axis  under  a  hammer  until  shortened  to  three  gauges 
of  the  pipe  in  height,  without  showing  cracks  or  flaws. 

(g)  A  piece  of  pipe  must  stand  flanging  cold,  the  width  of  the  flang- 
ing to  be  one-fourth  of  the  inside  diameter  of  the  pipe. 

(h)  Hot  or  Fire-Crack  Test. — Pieces,  2  feet  long,  cut  from  each  test 
specimen,  shall  be  heated  to  about  300°  F.,  and  must  then  stand  plunging 
into  ice-cold  water  without  showing  cracks. 


l88  DNGINEIERING   CHEMISTRY 

(i)  Cold-Bending  Tests  — "Each,  test  specimen,  cold,  shall  be  sawed 
through  the  axis  for  a  distance  of  i  foot,  then  the  split  parts  folded  back 
across  the  grain,  flat  on  themselves,  without  showing  fracture. 

These  tests  shall  be  made  on  each  of  the  i  per  cent,  test  pipes,  and 
the  test  specimens  shall  be  furnished  at  the  contractor's  expense. 

If  any  one  of  these  pipes  selected  for  test  fails,  the  naval  inspector 
will  select  two  extra  pipes  from  the  same  lot  and  put  them  through  the 
same  test  as  the  pipe  that  failed,  and  both  of  these  pipes  must  be  found 
satisfactory  in  order  that  the  lot  may  be  passed.  The  failure  to  pass 
satisfactorily  any  one  of  the  tests  will  reject  the  lot. 

All  pipe  shall  be  up  to  the  gauge  ordered.  Each  large  single  pipe  or 
bundle  of  small  pipes  will  be  marked  with  the  name  of  the  vessel  for 
which  it  is  intended,  or  with  the  number  of  the  order.  The  standard 
weight  for  seamless  "Benedict  nickel"  pipe  will  be  0.314  pound  per  cubic 
inch  of  material. 

Specifications  for  Seamless  Tubes  for  Condensers 
and  Feed-Water  Heaters. 

Material. — The  tubes  may  be  made  of  any  one  of  the  following  com- 
positions, as  required  by  machinery  specifications  or  ordered  on  requisi- 
tion, viz.,  70  copper,  29  zinc,  i  tin,  which  need  not  be  tinned ;  or  60  copper 
and  40  zinc,  which  must  be  tinned  inside  and  outside ;  or  Benedict  nickel, 
which  must  not  be  tinned. 

In  every  case  all  the  metals  used  must  be  of  the  purest  commercial 
quality. 

Test  Specimens. — The  naval  inspector  shall  select  at  random  from 
the  finished  tubes,  when  ready  for  shipment,  a  number  of  tubes  equal  to 
I  per  cent,  of  the  entire  order,  for  tests.  These  test  tubes  will  be  exclusive 
of  the  number  required  on  the  order  and  'will  be  furnished  at  the  con- 
tractor's expense. 

Weight. — All  of  the  test  tubes  are  to  be  weighed  together,  and  their 
average  weight  taken  to  represent  the  weight  of  the  whole  order.  All 
tubes  must  be  up  to  the  required  gauge  on  the  thinnest  side.  An  excess 
of  weight  of  not  more  than  5  per  cent,  will  be  allowed  for  all  tubes. 

Tubes  of  70-29-1  mixture  must  weigh  not  less  than  0.308  pound  per 
cubic  inch  of  metal. 

Tubes  of  60-40  mixture  must  weigh  not  less  than  0.298  pound  pei" 
cubic  inch. 

Benedict  nickel  tubes  shall  weigh  5  per  cent,  more  than  the  60-40 
mixture. 

Hot  or  Fire-Crack  Test. — Pieces  2  feet  long  cut  from  each  test  tube 
will  be  heated  to  about  300°  F.,  and  at  that  temperature  must  stand 
plunging  in  ice-cold  water  without  showing  cracks. 


EJNGINKKRING   CHEjMISTRY  189 

Cold-Bending  Tests. — Pieces  2  feet  long  cut  from  each  test  tube  and 
sawed  longitudinally  for  a  distance  of  i  foot  must  stand  opening  out 
flat  and  folding  flat  back  cold  across  the  grain  without  showing  signs  of 
fracture. 

Surface  Inspection. — All  tubes  must  be  seamless,  true  to  form,  of  an 
equal  thickness  throughout,  of  workmanlike  finish,  free  from  cracks, 
seams,  and  other  defects,  and  stiff  enough  to  lie  straight  when  resting  on 
supports  6  feet  apart. 

Tinning  and  Annealing.— AW  tubes  of  60  per  cent,  copper  and  40 
per  cent,  zinc  must,  after  final  drawing,  be  annealed,  acid  cleaned,  dipped 
in  molten  tin,  and  then  immediately  wiped  with  hempen  tow  inside  and 
out  to  insure  their  being  smooth  on  both  surfaces.  All  tubes  of  70  per 
cent,  copper  and  29  per  cent,  zinc  and  i  per  cent,  tin  must  be  annealed 
and  acid  cleaned.     Benedict  nickel  tubes  shall  not  be  annealed.  • 

The  amount  of  annealing  required  for  condenser  tubes  shall  be  suffi- 
cient to  enable  the  tubes  to  pass  the  physical  tests,  and  shall  be  sufficient 
to  permit  the  tubes  to  be  properly  packed  in  the  tube  sheet  without 
distortion. 

Tubes  for  feed-water  heaters  and  gland  stock  and  such  other  tubes 
(except  Benedict  nickel)  as  are  larger  and  thicker  than  condenser  tubes, 
must  be  sufficiently  annealed  to  prevent  cracking. 

Benedict  nickel  tubes  are  distinguished  from  brass  by  their  greater 
hardness  and  density  and  by  their  color,  which  is  like  that  of  tin,  and  is 
uniform  throughout  the  material. 

Water-Pressure  Tests. — All  finished  tubes  shall  be  subjected  to  1,000 
pounds  internal  water  pressure  without  showing  weakness  or  defect. 

Specifications  for  White  Metal. 

For  Anti- Friction  Linings. 

Material. — The  composition  shall  consist  of  3.7  per  cent,  of  the  best 
refined  copper,  88.8  per  cent.  Banca  tin,  7.5. per  cent,  of  the  regulus  of 
antimonj^  and  shall  be  well  fluxed  with  borax  and  resin  mixing. 

When  practicable,  the  weighing  and  mixing  of  the  metals  will  be 
witnessed  by  a  Government  inspector.  Otherwise  as  many  chemical 
analyses  will  be  taken  as,  in  the  judgment  of  the  naval  inspector,  will 
show  that  the  material  is  of  the  proper  composition. 

If  by  reason  of  scarcity  Banca  tin  cannot  be  procured,  another  stand- 
ard brand  of  tin  may  be  proposed,  subject  to  the  approval  of  the  Bureau 
of  Steam  Engineering. 

Specifications  for  Manganese-Bronze  Castings. 

The  castings  must  be  made  in  accordance  with  the  drawings  and 
specifications — sound,  clean,   free   from  blowholes,  porous  places,   cracks, 


190  DNGINS^RING   CHEMISTRY 

or  any  other  defects  which  will  materially  affect  their  strength  or  appear- 
ance or  which  indicate  an  inferior  quality  of  metal. 

In  the  case  of  screw  propellers  coupons  will  be  cast  attached  to  the 
hub  and  to  each  blade;  the  coupons  will  be  cast  in  a  horizontal  position, 
and  those  on  the  blades  will  be  attached  at  half  the  distance  from  the 
root  to  the  periphery.  The  coupons  will  be  cast  2  inches  in  diameter 
and  turned  down  as  required  by  specification.  The  coupons  are  to  have 
no  treatment  other  than  machining  to  reduce  them  to  the  proper  diameter. 
For  castings  weighing  over  200  pounds  test  pieces  or  coupons  shall  be 
taken  in  such  number  and  from  such  parts  of  the  casting  as  will  thor- 
oughly exhibit  the  quality  of  the  metal. 

Castings  weighing  less  than  200  pounds  may  be  tested  by  lots,  each 
lot  to  be  represented  by  two  test  pieces.  If  the  castings  are  too  small 
for  the  attachment  of  coupons,  the  test  pieces  may  be  cast  separately  from 
the  same  metal  under  as  nearly  as  possible  the  same  condition  as  the 
casting. 

Coupons  shall  not  be  detached  from  castings  until  they  are  stamped 
by  the  inspector.  If  test  pieces  are  cast  separately  from  the  casting, 
they  must  be  cast  in  the  presence  of  the  inspector  and  stamped  by  him  as 
soon  as  they  are  taken  out  of  the  molds. 

The  test  pieces  shall  show  an  ultimate  tensile  strength  of  not  less 
than  60,000  pounds  per  square  inch,  an  elastic  limit  of  not  less  than 
30,000  pounds  per  square  inch,  and  an  elongation  of  not  less  than  20 
per  cent,  in  2  inches. 

The  color  of  the  fractured  section  of  the  test  pieces  and  the  grain 
of  the  metal  must  be  uniform  throughout. 

Specifications  for  Journal  Boxes  and  Guide  Gibs,  and  Other  Parts 
of  the  Same  Composition. 

Material — All  metals  used  for  this  composition  must  be  of  the  purest 
commercial  quality. 

Analyses. — The  naval  inspector  will  take  drillings  for  analyses  and 
these  must  show  that  the  composition  consists  of  83  per  cent,  copper, 
13.5  per  cent,  tin  and  3.5  per  cent,  zinc,  no  component  to  vary  more  than 
I  per  cent,  above  or  below  the  amounts  specified. 

Specifications  for  Brazing  Metal. 

Used  Principai^ly  for  Copper  Pipe. 

The  inspection  of  this  metal  shall  conform  to  the  "General  instruc- 
tions for  the  inspection  of  copper,  brass,  and  bronze  material  coming 
under  the  cognizance  of  the  Bureau  of  Steam  Engineering." 

Material. — This  composition  shall  be  made  of  materials  of  the  purest 
commercial  quality. 


Engindkring  chemistry  191 

The  naval  inspector  will  take  drillings  for  analyses.  The  analyses 
shall  show  that  the  composition  consists  of  not  less  than  84  per  cent,  nor 
more  than  86  per  cent,  copper  and  the  remainder  zinc. 

Specifications  for  Rolled  Copper,  Muntz  Metal,  and  Brass  Sheets, 
Plates,  and  Rods. 

The  inspection  must  conform  to  the  "General  instructions  for  the 
inspection  of  material  coming  under  the  cognizance  of  the  Bureau  of 
Steam  Engineering." 

Material.— AW  metal  used  either  alone  or  in  the  manufacture  of  alloys 
must  be  of  the  purest  commercial  quality.  The  copper  must  be  best  Lake 
copper,  or  its  equivalent. 

Analyses. — The  naval  inspector  will  take  drillings  for  analyses.  An 
analysis  of  the  copper  sheets,  plates,  and  rounds  must  show  that  they 
contain  not  less  than  99.5  per  cent,  pure  copper.  An  analysis  of  Muntz 
metal  must  show  not  less  than  59  per  cent,  copper  and  the  remainder 
zinc.  An  analysis  of  brass  must  show  that  it  is  of  the  specified  com- 
position, no  component  varying  more  than  i  per  cent,  in  amount  above 
or  below  that  specified. 

Surface  Inspection. — The  sheets,  plates,  and  rounds  must  be  free 
from  all  surface  defects ;  the  sheets  and  plates  must  be  cut  to  the  dimen- 
sions ordered.  They  are  not  to  be  less  than  the  calculated  weight,  taking 
the  weight  of  i  cubic  inch  of  hot-rolled  copper  to  be  0.320  pound,  i  cubic 
inch  of  cold-rolled  copper  0.323  pound,  i  cubic  inch  of  rolled  Muntz  metal 
0.296  pound,  and  i  cubic  inch  of  rolled  brass  0.297  to  0.313  pound,  accord- 
ing to  its  composition.  A  variation  of  2^/2  per  cent,  under  gauge  will 
be  allowed. 

Tolerance  for  Bxcess  of  Weights. — An  excess  of  weight  of  5  per  cent, 
will  be  allowed  on  all  sheets  up  to  60  inches  wide.  For  all  sheets  above 
60  inches  wide  a  tolerance  of  8  per  cent,  will  be  allowed. 

Specifications  for  Copper  Pipes. 

The  pipe  must  be  made  of  best  Lake  copper,  or  its  equivalent,  and  a 
chemical  analysis  must  show  that  the  metal  is  99.5  per  cent,  pure  copper. 
The  naval  inspector  will  take  drillings  for  analyses. 

The  pipe  must  be  free  from  indentations,  cracks,  flaws,  or  other  sur- 
face defects,  inside  and  outside,  perfectly  round,  of  the  specified  diameter 
and  thickness  in  all  parts,  except  as  provided  in  special  cases.  All 
straight  sections  of  pipe  6  inches  in  diameter  (inside)  or  less  shall  be 
seamless  drawn. 

Each  pipe  must  withstand  an  internal  hydraulic  pressure  which  will 
subject  the  metal  to  a  stress  of  6,000  pounds  per  square  inch,  the  test 
pressure  being  calculated  by  the  following  formula  for  thin  hollow  cylin- 


192  KNGINEDRING    CHEMISTRY 

ders,  but  in  no  case  will  a  test  pressure  of  over  1,000  pounds  per  square 
inch  per  gauge  be  required: 

in  which 

p  :=  safe  internal  pressure ; 

d  =  inside  diameter  in  inches ; 

s  ^=  safe  tensile   strength  of  material  =  6,000  pounds  per  square 

inch; 
t  =z  thickness  of  pipe  in  inches. 


X /■ 


y^ 


8"- 


A. 


Every  pipe  must  be  perfectly  tight  under  pressure  and  show  no  signs 
of  bulging  cracks,  flaws,  porous  places,  or  other  defects. 

A  strip  i^  inches  wide  will  be  taken  from  each  lot  of  2,000  pounds 
or  less  of  pipe  and  must  stand  the  following  tests : 

(a)  If  less  than  ^  inch  thick,  it  must  stand  bending  flat  back  cold 
after  being  annealed. 

(b)  If  yi  inch  or  over,  it  must  bend  back  after  being  annealed  until 
the  ends  are  parallel  and  the  inner  radius  of  the  bend  is  equal  to  the 
thickness  of  the  piece. 

(c)  In  every  case  the  ends  of  the  bending  test  pieces  shall  stand 
hammering  down  hot  to  a  knife  edge  without  showing  signs  of  cracks. 
The  pipe  to  stand  flanging  without  defects. 

Pipes  of  2  inches  inside  diameter  and  over,  for  steam  or  feed  pipes 
or  other  such  high  pressure,  are  to  be  subject  to  tensile  tests,  one  piece  of 
pipe  from  each  lot  of  1,000  pounds  or  less  being  selected  to  represent 
the  lot.  If  the  pipes  are  from  2  to  6  inches  inside  diameter,  they  will 
be  cut  circumferentially.  The  test  pieces  will  be  heated  to  a  cherry  red 
and  straightened  when  hot,  then  machined  to  the  shape  shown  in  the 
sketch,  care  being  taken  to  have  the  brazed  seam,  if  any,  between  the 
measuring  points. 

For  thickness  up  to  and  including  ^  inch,  the  width  of  the  narrow 
part  of  the  test  piece  shall  be  about  i>4  inches.  For  thicker  pieces  the 
width  shall  be  such  as  to  give  a  cross  section  of  about  half  a  square  inch, 
but  the  breadth  shall  not  in  any  case  be  less  than  the  thickness.  The 
rolled  surfaces  are  not  to  be  machined,  but  to  be  left  in  their  original 
condition. 

The  test  piece   must   show   an   ultimate  tensile   strength   after   being 


ENGINEERING    CHEMISTRY  I93 

annealed  of  at  least  28,000  pounds  per  square  inch  for  all  pipe,  and  an 
elongation  of  at  least  25  per  cent,  in  8  inches  in  the  case  of  seamless  pipe. 
Thickness. — Every   pipe    must    be    of    the    specified    thickness    in    the 
thinnest  part. 

Weight. — The  weight  of  every  pipe  must  be  at  least  equal  to  the 
calculated  weight,  on  the  basis  of  i  cubic  inch  of  copper  pipe  weighs 
0.323  pound.  An  excess  of  weight  equal  to  5  per  cent,  of  the  calculated 
weight  will  be  allowed. 

Specifications  for  Phosphor  Bronze. 

Used  Principai^ly  for  Pump  Rods  and  Vai.ve  Springs  Exposed. 
TO  THE  Action  oe  Sea  Water. 

Rounds,  whether  cast,  rolled,  or  forged,  shall  have  an  ultimate  tensile 
strength  and  elongation  of  50,000  pounds  and  25  per  cent,  respectively. 

Note. — The  test  pieces  are  to  be  as  nearly  as  possible  of  the  same 
diameter  as  the  rounds,  or  else  they  are  to  be  not  less  than  14  inch  in 
diameter  and  taken  at  a  distance  from  the  circumference  equal  to  one-half 
the  radius  of  the  round. 

Phosphor  bronze  spring  wire  shall  be  hard  and  elastic. 

The  naval  inspector  will  take  drillings  for  analyses,  and  these  shall 
show  not  less  than  85  per  cent,  copper,  not  less  than  3  per  cent,  tin,  and 
not  less  than  o.oi  per  cent,  phosphorus,  the  balance  to  be  made  up  of 
whatever  components  the  manufacturers  consider  best  suited  to  produce 
a  composition  of  the  maximum  strength,  and  incorrodible  in  sea  water. 

Specifications  for  Rolled  Bronze. 

(Plates,  Shapes,  and  Rounds.) 

The  inspection  must  conform  to  the  "General  instructions  for  the 
inspection  of  copper,  brass,  and  bronze  material  coming  under  the  cog- 
nizance of  the  Bureau  of  Steam  Engineering." 

The  naval  inspector  will  take  drillings  for  chemical  analyses.  The 
analyses  must  show  that  the  alloy  is  composed  of  not  less  than  60  per 
cent,  nor  more  than  63  per  cent,  copper;  not  less  than  J^  of  i  per  cent, 
nor  more  than  1J/2  per  cent,  tin  and  the  remainder  zinc,  with  such  small 
quantities  of  other  ingredients  as  a  manufacturer  may  think  necessary  in 
the  case  of  proprietary  materials. 

All  bars  are  to  be  cleaned  and  straightened  and  must  stand : 

(a)  Being  hammered  hot  to  a  fine  point. 

(b)  Being  bent  cold  through  an  angle  of  120°  and  to  a  radius  equal 
to  the  diameter  or  thickness  of  the  bars. 

If  the  metal  is  to  be  rolled  into  rods   for  bolts  or  other  important 
13 


194  ENGINEERING   CHEMISTRY 

parts  subject  to  stress,  one  test  piece  for  every  lot  of  400  pounds  or  less 
shall  show  the  following  results  : 


Ultimate  tensile  strength 
per  square  inch 

Elastic  limit 

Elongation  per  cent, 
in  2  inches 

Not  less  than  60,000 
pounds. 

At  least  one-half  ultimate 
tensile  strength 

Not  less  than  25  per 
cent. 

In  the  case  of  large  lots  the  number  of  test  pieces  to  be  left  to  the 
judgment  of  the  naval  inspector. 

Various  composition  materials,  otherwise  conforming  to  the  specifica- 
tions but  manufactured  under  proprietary  processes  or  having  proprietary 
names,  will  be  accepted  as  rolled  bronze.  ~ 

Sheet  Brass  (Composition). 
Sixty  to  70  per  cent,  pure  copper. 

Forty  to  30  per  cent,  pure  zinc,  and  not  more  than  five-tenths  of  i 
per  cent.  lead. 

MoNEi.  MetaIv. 

Chemical  composition  of  monel  metal  to  be  not  less  than  60  per  cent, 
nickel  and  the  balance  copper,  other  elements  in  small  percentages  without 
being  detrimental  to  its  physical  qualities. 

Navy  mixture  No.  i,  for  rods,  tubes,  and  similar  material. 

Minimum  tensile  strength  per  square  inch,  80,000  pounds ;  minimum 
elastic  limit,  50,000  pounds ;  minimum  elongation  in  2  inches,  20  per  cent., 
and  to  stand  cold  bend  of  180°,  about  an  inner  diameter  of  i  inch. 

Navy  mixture  No.  2,  for  castings  and  similar  material. 

Minimum  tensile  strength  per  square  inch,  60,000  pounds;  minimum 
elastic  limit,  35,000  pounds ;  minimum  elongation  in  2  inches,  25  per  cent., 
and  to  stand  cold  bend  of  180°,  about  an  inner  diameter  of  i  inch. 

Specifications  for  Pig  Lead. 

1.  Pig  lead  will  be  required  for  either  as  No.  i  or  No.  2.  No.  i  grade 
is  for  foundry  use,  and  No.  2  grade  is  for  weights  and  ballast. 

2.  No.  I  pig  lead  to  be  of  the  best  quality  and  practically  free  from 
all  impurities.  To  show  on  analysis  not  less  than  99.5  per  cent,  of 
metallic  lead. 

3.  No.  2  pig  lead  to  be  of  good  commercial  grade  and  to  show  on 
analysis  not  less  than  97.5  per  cent,  of  metallic  lead. 

References. 

"Rapid  Analysis  of  Alloys  for  Tin,  Antimony  and  Arsenic,"  by  F.  A.  Stief, 
Jour.  hid.  and  Bng.  Cheni.,  Mar.,  191 5. 


ENGINEERING   CHEMISTRY  I95 

"The  Electrolytic  Separation  of  Zinc,  Copper  and  Iron  from  Arsenic,"  by 
A.  K.  Balls  and  C.  C.  McDonnell,  Jour.  Ind.  and  Bng.  Chem.,  Jan., 
1915. 

"Determination  of  Tin  in  Metal  Foil  of  Pb,  Sn  and  Sb,"  Chem.  Abstracts, 
1 914,  p.   1464. 

"Self-lubricating  Bearing  Metals,"  Chem.  Abstracts,  1914,  p.  11 58. 


THE  CHEMICAL  AND  PHYSICAL  EXAMINATION  OF 
PORTLAND  AND  NATURAL  CEMENTS. 

The  definition  of  Portland  cement  as  adopted  by  the  Verein 
Deutscher  Portland  Cement  Fabrikanten  is,  that  it  is  a  product 
obtained  by  crushing  after  heating  to  the  sintering  point,  a  mix- 
ture of  limestone,  marl,  chalk  or  hydraulic  limestone  with  clay 
and  is  to  be  distinguished  from  "slag"  cement  (a  form  of  Port- 
land) as  the  latter  is  formed  by  the  following  processes:  (i) 
Granulation  of  the  slag,  (2)  drying  of  the  slag,  (3)  mixing  with 
a  suitable  proportion  of  slaked  lime,  (4)  grinding  of  the  mix- 
ture. The  Portland  cement  of  the  United  States  comprises 
those  cements  which  are  produced  by  the  burning  to  the  sin- 
tering point  and  grinding  of  artificial  mixtures  of  limestone  (or 
marl,  chalk,  or  hydraulic  limestone)  and  clay,  or  slag  sand.^ 

After  manufacture  it  is  practically  CagSiOg,  and  is  quite  dis- 
tinct from  another  product  made  and  largely  consumed  here 
called  "hydraulic  cement,  or  natural  cement." 

Experience  has  shown  that  Portland  cements  containing  over 
5  per  cent,  of  magnesia  (MgO)  are  inferior  in  lasting  qualities, 
and  by  the  gradual  absorption  of  water  produce  cracking  and 
disintegration. 

The  "Ecole  Nationale,"  of  Paris,  rejects  all  cements  containing 
over  2.5  per  cent,  of  sulphuric  acid.  Thus,  if  upon  chemical 
analysis,  magnesia  is  found  present  in  amounts  over  5  per  cent., 
carbonic  and  sulphuric  acids  in  amounts  over  2.5  per  cent.,  the 
cement  can  be  condemned  at  once  ivithout  any  mechanical  tests. 
Therefore,  it  is  evident  that  a  careful  test  of  a  Portland  cement 
requires :     ( i )  a  chemical  analysis  to  determine  the  proportion 

^J.  Soc.  Chem.  Ind.,   1901,  p.   1212;  "Historical  Sketch  of  Slag  Cement,"  by  Pro- 
fessor William  Kendrick,  Scientific  American  Supplement,   May  25,    1901. 


196  ENGINEERING   CHEMISTRY 

of  the  ingredients,  and  (2)  the  mechanical  or  physical  tests  to 
determine  fineness,  tensile  strength,  and  resistance  to  crushing.^ 

The  scheme  on  page  197  is  arranged  to  show  the  method  of 
making  a  cement  analysis. 

In  order  to  more  fully  explain  the  scheme  for  the  analysis  of 
Portland  and  natural  cements,  the  following  analysis  of  a  Port- 
land cement  is  given : 

Grams 

Amount  of  cement  taken 2.000 

(i)   Crucible   +   SiO. 11.205 

Crucible    10.721 

SiO,   0484 

0.484  X    100  ^     c,r^ 

— ^  ^     =  24  20  per  cent.  SiO.^. 

Grams 

(2)  Crucible  +  AI2O3  (in  soluble  residue) 10.743 

Crucible    10.721 

AI2O3   0.022 

=1.10  per  cent.  AloOj  in  insoluble  residue. 

Grams 

(3)  Crucible  +  FcoO. 10.745 

Crucible    10.721 

Fe^Oa  0.024 

0.024  X  2.50  X   100  4.     T?     r^ 

^-^ ^^—^ z=  3.00  per  cent.  Fe^O^. 

Grams 

(4)  Crucible  +  AW, 10.762 

Crucible  10.721 

AI2O3 0.041 

0.041     X    2.5    X     100  ^        A1    ^ 

— -^—^ — ^^-^^ =5.12  per  cent.  AljO.,. 

5.12  per  cent.  +  i.io  per  cent,   (from  (i))  =  5.12  per  cent.  AI2O3. 

Grams 

(5)  Crucible  -\-  CaO 12.2223 

Crucible    11. 7210 

CaO    0.5013 

0-5013  X  2.50  X  100        .    .    ^^^  ^^„,    p,  p, 
=  62.67  V^^  cent.  CaU. 

^  "Portland   Cement   Manufacture,"    by   Edwin    C.    Eckle,   Municipal   Engineertng, 
January,    1904. 


.  o 


Kb 
.  a 


-3 


as 

s  ^ 


g   5^ 

O     £•= 


^o 


4^  ^ 


JC  to 


E  =  E 
2  ^>> 

N  o  bfl 

V  CO 


is 


S^ 


05 


'S^g'H^.-:ls>'1 


i-^"-^?-?t-'5:;2S<5' 


«3 


J3kT 


M^ 


^3  C 


CO  ^ 


o 

50 

o 

-o 
CO 


in  o 
V  o 


■E  X 


.S  *i  (LI  10  O 
■^  ts  t?  _ 

J5  o    .5  if! 
7  ^H  o  ^ 

11  *"■     in  O 

2^'ns- 

Ui  O  —    ^"O 

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ri   O   fj    01  "^ 

fl  rt  a  w  > 


•52 


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.2n  >  ^-  4; 

■P  y  p  o  -ti 

_-0«S4i 


a  c  w -a  - 
.2  i)  n  c 


fe  i*  k_r  M  4.  lT'o  "CO  c:i  >>  a  "5  ^ 


-« --^  s  o 

-aw        ^ 

t-u-  V  4^^ 


l«5-; 


-o^  "«ii- 


CO  >     *->     O 
Tj  CO  CO  nrj j:      4>  ^\: 


I   ■*  -  tn  o  • 
lO  3  CO  o. 


^u  ^.ij  a.-:i  <uU 


aT      C       .- 

"O  .TT  Ai  .,_)  *j 
ro  C  H  to  .«   »- 

"^Q  S'-o  &ii 


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e 

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4^  ti 


Co 


"S         4>  «. 


a  =  CO  3  CO  *j 
•2  TO^'<«  ^  >>■ 


«<J  *jc0  ^!>i^co.i!rP 


Q  ^ 


bfi. 


,4^  M 


.5  o    £ 
i3>    H 


•M      C    .,     ■«•     '  CO 


*^       Q  CO 


1^ 

fi 


•-    bfl 

XI     CO 

«  a 


A    c 


5  s 


2  H 


3    u 

o   o 


-   a  3 


a.  V 


-6.3  2i 

sis 


CO     w  __ 
"55    -^   "O 


198 


DNGINEKRING   CHEMISTRY 


Grams 

(6)  Platinum  dish  +  MgSO*  +  NaoS04 33820 

Platinum  dish 33755 


MgS04  +  Na2S04 0.065 

Determining  the   Magnesia   as  1 

Mg,PA. 

Crucible  +  Mg^P^O^ 

Crucible 


10.7483 
10.7210 


MgS04     0.0294 


Mg-AO; 0.0273  '1- 

0.0273    gram     MgaPaO^     corre- 
sponds to 

0.0294  gram  of  MgSO^ — 

which     is    subtracted    from     0.065     gram 

Na,SO,  +  MgSO,.  J       Na^SO,  0.0356 

The  0.0294  gram  MgS04  corresponds  to  0.0098  gram  of  MgO. 

0.0098  X  2.5  100  ,,   ^ 
^—^ — =  1.22  per  cent.  MgO. 

The  0.0356  gram  NaaSO*  corresponds  to  0.0155  gram  NaaO. 

0.0,55x^2.5x100  _  ^^  p^^  ^^^^  j^^^Q  ■ 

Grams 

Crucible  +  BaS04 10.729 

Crucible    10.721 


BaS04 


0.008 


SOs  =  0.0027  gram 
0.0027  X  5  X  100 


0.67  per  cent.  SO3 


re:sum]§;. 


SiO.  

AI2O3   

Fe^Oa  

CaO   

MgO    

Na>0   1.96 

SO.    0.67 


Per  cent. 
,    24.20 

6.22 
,  3.00 
,    62.67 

1.22 


Total 


99-94' 


^  Consult    Stevens    Institute    Indicator,    "Determination    of    Alkalies    in    Portland 
Cement,"  by  Thomas  B.   Stillman,  October,    1901. 


ENGINEERING   CHEMISTRY 


199 


The   following  well-known  brands  of  cement  were  analyzed 
in  my  laboratory : 


SiOg  • .  • . 
AI2O, . . .  • 
Fe,03.... 
CaO-... 
MgO  . . . . 

K2O 

NagO  . . . . 

SO3 

CO2   .    •• 

Total 


Burham's 
(per  cent. 


21.70 
6.82 

2.37 
62.26 
1.48 
T.84 
0.98 
1.20 
1.30 

99-95 


Dyckerhoff's 
(per  cent.) 


19-05 
7.90 
5-48 

63.62 
1.87 
0.78 
0.36 
0.94 


Saylor's 
(per  cent.) 


21.25 

4.21 

8.25 

61.25 

I -50 

I. or 
0.99 
1.38 


99.84 


In  some  cements  quartz  is  a  constituent  in  amounts  varying 
from  0.5  to  6  per  cent.  It  can  be  separated  from  combined  silica 
by  the  method  of  Fresenius.^ 

Where  carbonic  acid  has  been  indicated  by  the  qualitative 
analysis,  the  quantitative  analysis,  for  this  constituent,  should  be 
made  upon  at  least  8  grams  of  the  cement. 

The  carbonic  acid  rarely  reaches  i  per  cent.,  and  while  it  is 
generally  absent  in  well-burned  cements,  it  is  by  no  means  an 
uncommon  constituent  to  the  amount  of  0.15-0.30  per  cent.,  as 
the  following  table  of  analyses  of  German  cements  will  show : 


CaO 

SiOg  .  •  • 
Fe^O,  ... 
A\,0,.... 
MgO  . . . . 
Alkalies  . 

SO3 

CO2 

Insoluble 


61.99 

23.69 

2.71 

8.29 

0.47 

0.95 
0.69 
0.27 
0.44 


62.89 
22.80 
3-40 
7.70 
1.20 
1.30 
0.71 


63.71 
25-37 
3-14 
4.31 
1.25 
0.84 
0.87 


63.27 

19.80 

3.22 

6.73 
2.02 
1.48 
1.08 
0.23 
1.38 


65.59 

22.85 

2.76 

5-51 
1.24 
0.92 
1.69 


59-96 
23.70 

3-'5 
8.20 
1. 00 
1.05 
0.88 
0.20 
0.80 


64.51 

22.38 

2.24 

9-45 


1.44 


60.81 
22.63 
2.42 
7.06 
2.89 
2.83 
0.47 
033 


Free  Lime  in  Portland  Cement. 

Free  lime  is  sometimes  found  in  Portland  cement.  Keiser  and 
Forder  give  a  process  for  determining  it  in  Amer.  Chem.  Jour- 
nal, 31,  153.     Consult  also:     "A  Rapid  Method  for  the  Deter- 

^  "Quantitative  Chemical  Analysis,"  p.  259. 


200 


V,  N  r.  f  N  K f% K  f  X  (>    ( '  f  f  i:  M  f  S'f  k  Y 


mination  of  JJme  in  Cement,"  by  liernard  Knright,  Jour  Amer. 
Chem.  Soc,  August,  1904,  pp.  jcxj3-ioo6. 

Slag  cement  can  be  distinguished  from  Portland  cement  by 
the  method  of  Seger  and  Cramer  (Chem.  Zcitung,  2y,  879; 
which  is  as  follows: 

Pass  the  material  through  a  ifxj-mesh  sieve  and  bc^il  50  grams 
with  100  cc,  of  water  for  3  hours,  kcej^ng  uj>  the  volume  of 
water  by  additions  from  time  to  time,  and  agitating  occasionally 
to  prevent  formation  of  lumps.  Filter,  wash  twice  with  hot 
water  and  dry  at  110°  to  120^  C,  In  i  gram  or  more  of  the  ma- 
terial determine  loss  on  ignition  {i.  e.,  water  of  hydration). 
Portland  showed  10.19  to  13.10  per  cent,  (average  11.46  per 
cent.)  slag  cement  gave  0.70  to  0.84  (average  0.78  per  cent.).' 

The  amount  soluble  in  water  also  differs.  Shaking  i  to  1.5 
grams  with  3  liters  of  freshly  boiled  water,  and  collecting  and 
weighing  the  residue  after  ignition,  indicated  that  there  was 
dissolved  out  from  Portland  cement  (28.7  to  42.8)  an  average 
of  37.15  per  cent.,  but  from  the  slag  cement  1.2  to  4.56  C average 
2.33)  per  cent. 

'the  rarer  constituents  found  in  3  samjjies  of  J^ehigh  I'cHtland 
cement  by  Meade,  "Portland  Cement,"  p.  32,  were  as  follows: 


No.  I  No.  a  No.  3 

(p«r  cent.)  (per  cent.)  (per  cent.) 


Titanic  acid 

Ferrous  oxitlc 

Manganous  oxide   

tjtrontiuin  oxide   

Calcium  sulphide 

Potash 

Soda 

Phosphorus  pentoxide  • . 


0.28 
0.23 
0,06 
6.08 
0,18 
0.50 
0.26 
0.25 


0.27 
0.16 
0,08 

0.09 
0.48 
0.31 
0.31 


0.32 
o.  1 1 
0,09 

a.07 

0.59 
0.38 
0.29 


Rapid  Determination  of  Lime   (CaO),  Without  Separation 

of  Silica,  Etc.,'  (Volumetric). 

Weigii  0.5  gram  of  cement  in  a  dry  5cx;  cc.  beaker  and  add, 

with  constant  stirring,  20  cc.  of  cold  water.    Break  up  the  lumps 

and  when  all   the  sample  is  in   suspension,  except   the    heavier 

1  R.  Waller:  The  School  of  Mines  Quarfrrlv,  Aptil    \u',a   p    mo. 
8  Chemical  Etigineer,  1,  p.  21. 


ENGINEERING   CHEMISTRY  201 

particles,  add  20  cc.  of  dilute  (1:1)  hydrochloric  acid  and  heat 
until  solution  is  complete.  This  usually  takes  from  5  to  6  min- 
utes. Heat  to  boiling,  add  dilute  ammonia  carefully  to  the  solu- 
tion until  a  slight  permanent  precipitate  forms.  Heat  to  boiling, 
add  10  cc.  of  a  10  per  cent,  solution  of  oxalic  acid.  Stir  until 
the  oxides  of  iron  and  aluminum  are  entirely  dissolved  and  only 
a  slight  precipitate  of  calcium  oxalate  remains.  Add  200  cc.  of 
boiling  water  and  20  cc.  saturated  solution  of  ammonium  oxalate 
to  completely  precipitate  the  lime.  Boil  for  a  few  minutes,  re- 
move from  the  heat,  allow  the  precipitate  to  settle  and  filter  on  a 
1 1 -centimeter  filter.  Wash  the  precipitate  and  filter  ten  times 
with  hot  water  using  not  more  than  lo  cc.  each  time. 

Remove  the  filter  from  the  funnel,  open  and  lay  against  the 
sides  of  a  beaker,  wash  from  the  paper  into  the  beaker,  with 
hot  water,  add  dilute  sulphuric  acid,  5  cc,  heat  to  80°  C.  and 
titrate  with  standard  permanganate  until  a  pink  color  is  obtained. 

(5.64  grams  KMnO^  in  i  liter  of  water,  i  cc.  corresponds  to 
0.005  gram  CaO.) 

Standard  Specifications  for  Cement. 
American  Society  for  Testing  Materials. 

Generai,  Observations. 

1.  These  remarks  have  been  prepared  with  a  view  of  pointing 
out  the  pertinent  features  of  the  various  requirements  and  the 
I)recautions  to  be  observed  in  the  interpretation  of  the  results  of 
the  tests. 

2.  The  committee  would  suggest  that  the  acceptance  or  re- 
jection under  these  specifications  be  based  on  tests  made  by  an 
experienced  person  having  the  proper  means  for  making  the 
tests. 

Specific  Gravity. 

3.  Specific  gravity  is  useful  in  detecting  adulteration.  The 
results  of  tests  of  specific  gravity  are  not  necessarily  conclusive 
as  an  indication  of  the  quality  of  a  cement,  but  when  in  com- 
bination with  the  results  of  other  tests  may  afford  valuable  in- 
dications. 


202 


ENGINEERING   CHEMISTRY 


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engineering  chemistry  203 

Fineness. 

4.  The  sieves  should  be  kept  thoroughly  dry. 

Time  of  Setting. 

5.  Great  care  should  be  exercised  to  maintain  the  test  pieces 
under  as  uniform  conditions  as  possible.  A  sudden  change  or 
wide  range  of  temperature  in  the  room  in  which  the  tests  are 
made,  a  very  dry  or  humid  atmosphere,  and  other  irregularities 
vitally  affect  the  rate  of  setting. 

Constancy  of  Voi^ume. 

6.  The  tests  for  constancy  of  volume  are  divided  into  two 
classes,  the  first  normal,  the  second  accelerated.  The  latter 
should  be  regarded  as  a  precautionary  test  only,  and  not  infalli- 
ble. So  many  conditions  enter  into  the  making  and  interpreting 
of  it  that  it  should  be  used  with  extreme  care. 

7.  In  making  the  pats  the  greatest  care  should  be  exercised 
to  avoid  initial  strains  due  to  molding  or  too  rapid  drying-out 
during  the  first  24  hours.  The  pats  should  be  preserved  under 
the  most  uniform  conditions  possible,  and  rapid  changes  of  tem- 
perature be  avoided. 

8.  The  failure  to  meet  the  requirements  of  the  accelerated 
tests  need  not  be  sufficient  cause  for  rejection.  The  cement  may, 
however,  be  held  for  28  days,  and  a  retest  made  at  the  end 
of  that  period,  using  a  new  sample.  Failure  to  meet  the  require- 
ments at  this  time  should  be  considered  sufficient  cause  for 
rejection,  although  in  the  present  state  of  our  knowledge  it  can- 
not be  said  that  such  failure  necessarily  indicates  unsoundness, 
nor  can  the  cement  be  considered  entirely  satisfactory  simply 
because  it  passes  the  tests. 

Specifications. 

GENERAL  CONDITIONS. 

1.  All  cement  shall  be  inspected. 

2.  Cement  may  be  inspected  either  at  the  place  of  manufac- 
ture or  on  the  work. 

3.  In  order  to  allow  ample  time   for  inspecting  and  testing, 


204 


ENGINEERING   CHEMISTRY 


the  cement  should  be  stored  in  a  suitable  weather-tight  building 
having  the  floor  properly  blocked  or  raised  from  the  ground. 

4.  The  cement  shall  be  stored  in  such  a  manner  as  to  permit 
easy  access  for  proper  inspection  and  identification  of  each  ship- 
ment. 

5.  Every  facility  shall  be  provided  by  the  contractor  and  a 
period  of  at  least  12  days  allowed  for  the  inspection  and  necessary 
tests. 

6.  Cement  shall  be  delivered  in  suitable  packages  with  the 
brand  and  name  of  manufacturer  plainly  marked  thereon. 

7.  A  bag  of  cement  shall  contain  94  pounds  of  cement  net. 
Each  barrel  of  Portland  cement  shall  contain  4  bags,  and  each 
barrel  of  natural  cement  shall  contain  3  bags  of  the  above  net 
weight. 

8.  Cement  failing  to  meet  the  7-day  requirements  may  be  held 
awaiting  the  results  of  the  28-day  tests  before  rejection. 

9.  All  tests  shall  be  made  in  accordance  with  the  methods 
proposed  by  the  Committee  on  Uniform  Tests  of  Cement  of  the 
American  Society  of  Civil  Engineers,  presented  to  the  Society 
January  21,  1903,  and  amended  January  20,  1904,  and  January 
15,  1908,  with  all  subsequent  amendments  thereto.  (See  adden- 
dum to  these  specifications.) 

10.  The  acceptance  or  rejection  shall  be  based  on  the  follow- 
ing requirements : 

NATURAL  CEMENT.^ 

11.  Definition.  This  term  shall  be  applied  to  the  finely  pul- 
verized product  resulting  from  the  calcination  of  an  argillaceous 
limestone  at  a  temperature  only  sufiicient  to  drive  off  the  carbonic 
acid  gas. 


'Hoffmann" 

"Cummings"     .... 

"Buffalo" 

"California" 

"Norton" 

James  River,  Virginia 
"Napanee" 


SiOa 


27.30 
26.69 
24.30 
24-34 
27.98 
25- 15 
19.90 


AloO, 


7.14 

7.2t 

2.61 
8.56 
7.28 
8.00 
5.92 


FeO 


1.80 
1.30 
6.20 
2.08 
1.70 
3-28 
1. 14 


CaO 


35-98 
43  12 
39-45 
61.62 
37-59 
49-53 
46.75 


MgO 


18.0 
1955 
6.16 
0.40 
15.00 
13.7S 
16.00 


K..O 
Na«0 


6.S0 
I-I3 
5-30 
2.00 
7.96 

802 


COoHoO. 
and  ios.s 


1. 00 
13.23 
0.80 

2-49 
0.26 
2.27 


A  few  analyses  here  given  will  indicate  the  variation  of  composition. 


e:ngine:ering  chemistry  205 

Fineness. 

12.  It  shall  leave  by  weight  a  residue  of  not  more  than  10  per 
cent,  on  the  No.  100,  and  30  per  cent,  on  the  No.  200  sieve. 

Time  of  Setting. 

13.  It  shall  not  develop  initial  set  in  less  than  10  minutes;  and 
shall  not  develop  hard  set  in  less  than  30  minutes,  or  in  more 
than  3  hours. 

TENS11.E  Strength. 

14.  The  minimum  requirements  for  tensile  strength  for  bri- 
quettes I  square  inch  in  cross  section  shall  be  as  follows,  and 
the  cement  shall  show  no  retrogression  in  strength  within  the 
periods  specified : 

Neat  Cement. 

Age  strength 

24  hours  in  moist  air 75  lbs. 

7  days  (i  day  in  moist  air,  6  days  in  water) 150  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water) 250  lbs. 

I  Part  Cement,  3  Parts  Standard  Ottawa  Sand. 

7  days  (i  day  in  moist  air,  6  days  in  water) 50  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water) 125  lbs. 

Constancy  of  Voi^ume. 

15.  Pats  of  neat  cement  about  3  inches  in  diameter,  ^  inch 
thick  at  center,  tapering  to  a  thin  edge,  shall  be  kept  in  moist  air 
for  a  period  of  24  hours. 

(a)  A  pat  is  then  kept  in  air  at  normal  temperature. 

(b)  Another  is  kept  in  water  maintained  as  near  70°  F.  as 
practicable. 

16.  These  pats  are  observed  at  intervals  for  at  least  28  days, 
and,  to  satisfactorily  pass  the  tests,  shall  remain  firm  and  hard 
and  show  no  signs  of  distortion,  checking,  cracking,  or  disinte- 
grating. 

PORTLAND  CEMENT. 

17.  Definition.  This  term  is  applied  to  the  finely  pulverized 
product  resulting  from  the  calcination  to  incipient  fusion  of  an 
intimate  mixture  of  properly  proportioned  argillaceous  and  cal- 
careous materials,  and  to  which  no  addition  greater  than  3  per 
cent,  has  been  made  subsequent  to  calcination. 


2o6  e:ngink^ring  chkmistry 

Spe)cific  Gravity. 

i8.  The  specific  gravity  of  cement  shall  not  be  less  than  3.10. 
Should  the  test  of  cement  as  received  fall  below  this  requirement, 
a  second  test  may  be  made  upon  a  sample  ignited  at  a  low  red 
heat.  The  loss  in  weight  of  the  ignited  cement  shall  not  exceed 
4  per  cent. 

Finkne:ss. 

19.  It  shall  leave  by  weight  a  residue  of  not  more  than  8 
per  cent,  on  the  No.  100,  and  not  more  than  25  per  cent,  on  the 
No.  200  sieve. 

TiMK   OF    SivTTlNG. 

20.  It  shall  not  develop  initial  set  in  less  than  30  minutes ;  and 
must  develop  hard  set  in  not  less  than  i  hour,  nor  more  than  10 
hours. 

Te:nsii.e:  Strength. 

21.  The  minimum  requirements  for  tensile  strength  for  bri- 
quettes I  square  inch  in  cross  section  shall  be  as  follows,  and 
the  cement  shall  show  no  retrogression  in  strength  within  the 
periods  specified : 

Neat  Cement. 

Age  Strength 

24  hours  in  moist  air 1 75  lbs. 

7  days  (i  day  in  moist  air,  6  days  in  water) 500  lbs. 

28  days  (1  day  in  moist  air,  2"]  days  in  water) 600  lbs. 

I  Part  Cement,  3  Parts  Standard  Ottawa  Sand. 

7  days  (i  day  in  moist  air,  6  days  in  water) 200  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water) 275  lbs. 

Constancy  of  Volume. 

22.  Pats  of  neat  cement  about  3  inches  in  diameter,  ^  inch 
thick  at  the  center,  and  tapering  to  a  thin  edge,  shall  be  kept  in 
moist  air  for  a  period  of  24  hours. 

(a)  A  pat  is  then  kept  in  air  at  normal  temperature  and  ob- 
served at  intervals  for  at  least  28  days. 

(&)  Another  pat  is  kept  in  water  maintained  as  near  70°  F. 
as  practicable,  and  observed  at  intervals  for  at  least  28  days. 


ENGINE^ERING   CHEMISTRY  20/ 

(c)  A  third  pat  is  exposed  in  any  convenient  way  in  an  atmos- 
phere of  steam,  above  boiUng  water,  in  a  loosely  closed  vessel  for 
5  hours. 

23.  These  pats,  to  satisfactorily  pass  the  requirements,  shall 
remain  firm  and  hard,  and  show  no  signs  of  distortion,  checking, 
cracking,  or  disintegrating. 

Sulphuric  Acid  and  Magnesia. 

24.  The  cement  shall  not  contain  more  than  1.75  per  cent, 
of  anhydrous  sulphuric  acid  (SO3),  nor  more  than  4  per  cent,  of 
magnesia  (MgO). 

Methods  for  Testing  Cement.^ 

Recommended  by  the  Special  Committee  on  Uniform  Tests  of 
Cement  of  the  American  Society  of  Civil  Engineers. 

Sampung. 

1.  Selection  of  Sample. — The  selection  of  samples  for  testing 
should  be  left  to  the  engineer.  The  number  of  packages  sampled 
and  the  quantity  taken  from  each  package  will  depend  on  the 
importance  of  the  work  and  the  facilities  for  making  the  tests. 

2.  The  samples  should  fairly  represent  the  material.  When 
the  amount  to  be  tested  is  small  it  is  recommended  that  i  barrel 
in  10  be  sampled ;  when  the  amount  is  large  it  may  be  impractic- 
able to  take  samples  from  more  than  i  barrel  in  30  or  50.  When 
the  samples  are  taken  from  bins  at  the  mill  for  each  50  to  200 
barrels  will  suffice. 

3.  Samples  should  be  passed  through  a  sieve  having  20  meshes 
per  linear  inch,  in  order  to  break  up  lumps  and  remove  foreign 
material;  the  use  of  this  .sieve  is  also  effective  to  obtain  a 
thorough  mixing  of  the  samples  when  this  is  desired.  To  de- 
termine the  acceptance  or  rejection  of  cement  it  is  preferable, 
when  time  permits,  to  test  the  samples  separately.  Tests  to  de- 
termine the  general  characteristics  of  a  cement,  extending  over 
a  long  period  may  be  made  with  mixed  samples. 

*  Accompanying  Final  Report  of  Special  Committee  on  Uniform  Tests  of  Cement 
of  the  American  Society  of  Civil  Engineers,  dated  January   17,   19 12. 


2o8  ENGINEERING   CHEMISTRY 

4.  Method  of  Sampling. — Cement  in  barrels  should  be  sampled 
through  a  hole  made  in  the  head,  or  in  one  of  the  staves  midway 
between  the  heads,  by  means  of  an  auger  or  a  sampling  iron 
similar  to  that  used  by  sugar  inspectors;  if  in  bags,  the  sample 
should  be  taken  from  surface  to  center;  cement  in  bins  should 
be  sampled  in  such  a  manner  to  represent  fairly  the  contents 
of  the  bin.  Sampling  from  bins  is  not  recommended  if  the 
method  of  manufacture  is  such  that  ingredients  of  any  kind  are 
added  to  the  cement  subsequently. 

Chemical  Anai^ysis. 

5.  Significance. — Chemical  analysis  may  serve  to  detect  adul- 
teration of  cement  with  inert  material,  such  as  slag  or  ground 
limestone,  if  in  considerable  amount.  It  is  useful  in  determining 
whether  certain  constituents,  such  as  magnesia  and  sulphuric 
anhydride,  are  present  in  inadmissible  proportions. 

6.  The  determination  of  the  principal  constituents  of  cement 
silica,  alumina,  iron  oxide,  and  lime,  is  not  conclusive  as  an  in- 
dication of  quality.  Faulty  cement  results  more  frequently  from 
imperfect  preparation  of  the  raw  material  or  defective  burning 
than  from  incorrect  proportions.  Cement  made  from  material 
ground  very  finely  and  thoroughly  burned  may  contain  much 
more  lime  than  the  amount  usually  present,  and  still  be  per- 
fectly sound.  On  the  other  hand,  cements  low  in  lime  may,  on 
account  of  careless  preparation  of  the  raw  material,  be  of  dan- 
gerous character.  Furthermore,  the  composition  of  the  product 
may  be  so  greatly  modified  by  the  ash  of  the  fuel  used  in  burn- 
ing as  to  affect  in  a  great  degree  the  significance  of  the  results 
of  analysis. 

7.  Methods. — The  methods  to  be  followed,  except  for  deter- 
mining the  loss  on  ignition,  should  be  those  proposed  by  the 
Committee  on  Uniformity  in  the  Analysis  of  Materials  for  the 
Portland  Cement  Industry,  reported  in  the  Journal  of  the  Society 
for  Chemical  Industry,  Vol.  21,  page  12,  1902;  and  published  in 
Engineering  News,  Vol.  50,  p.  60,  1903;  and  in  Engineering 
Record,  Vol.  48,  p.  49,  1903,  and  in  addition  thereto,  the  follow- 
ing: 


ENGINEERING    CHEMISTRY  209 

(a)  The  insoluble  residue  may  be  determined  as  follows  :  To  a 
i-gram  sample  of  the  cement  are  added  30  cc.  of  water  and  10  cc. 
of  concentrated  hydrochloric  acid,  and  then  warmed  until  effer- 
vescence ceases,  and  digested  on  a  steam  bath  until  dissolved. 
The  residue  is  filtered,  washed  with  hot  water,  and  the  filter 
paper  and  contents  digested  on  the  steam  bath  in  a  5  per  cent, 
solution  of  sodium  carbonate.  This  residue  is  filtered,  washed 
with  hot  water,  then  with  hot  hydrochloric  acid,  and  finally  with 
hot  water,  and  then  ignited  at  a  red  heat  and  weighed.  The 
quantity  so  obtained  is  the  insoluble  residue. 

(b)  The  loss  on  ignition  shall  be  determined  in  the  following 
manner:  One-half  gram  of  cement  is  heated  in  a  weighed  plat- 
inum crucible,  with  cover,  for  5  minutes  with  a  Bunsen  burner 
(starting  with  a  low  flame  and  gradually  increasing  to  its  full 
height)  and  then  heated  for  15  minutes  with  a  blast  lamp;  the 
difference  between  the  weight  after  cooling  and  the  original 
weight  is  the  loss  on  ignition.  The  temperature  should  not  ex- 
ceed 900°  C,  or  a  low  red  heat;  the  ignition  should  preferably 
be  made  in  a  muffle. 

Specific  Gravity. 

8.  Significance. — The  specific  gravity  of  cement  is  lowered  by 
adulteration  and  hydration,  but  the  adulteration  must  be  con- 
siderable to  be  detected  by  tests  of  specific  gravity. 

9.  Inasmuch  as  the  differences  in  specific  gravity  are  usually 
very  small,  great  care  must  be  exercised  in  making  the  determin- 
ation. 

10.  Apparatus. — The  determination  of  specific  gravity  should 
be  made  with  a  standardized  Le  Chatelier  apparatus.  This  con- 
sists of  a  flask  (D),  Fig.  22,  of  about  120  cc.  capacity,  the  neck 
of  which  is  about  20  centimeters  long;  in  the  middle  of  this  neck 
is  a  bulb  (C),  above  and  below  which  are  two  marks  (F)  and 
(H)  ;  the  volume  between  these  two  marks  is  20  cc.  The  neck 
has  a  diameter  of  about  9  millimeters,  and  is  graduated  into 
tenths  of  cubic  centimeters  above  the  mark  (P). 

11.  Benzene  (62°  Baume  naphtha)  or  kerosene  free  from 
water  should  be  used  in  making  the  determination. 

14 


2IO 


Kngine:kring  ch:e:mistry 


12.  Method. — The  flask  is  filled  with  either  of  these  liquids  to 
the  lower  mark  (B),  and  64  grams  of  cement,  cooled  to  the  tem- 
perature of  the  liquid,  is  slowly  introduced  through  the  funnel 
{B),  (the  stem  of  which  should  be  long  enough  to  extend  into 
the  flask  to  the  top  of  the  bulb  (C),  taking  care  that  the  cement 


Fig.   22. — Le   Chatelier's  specific  gravity  apparatus. 

does  not  adhere  to  the  sides  of  the  flask,  and  that  the  funnel  does 
not  touch  the  liquid.  After  all  the  cement  is  introduced,  the 
level  of  the  liquid  will  rise  to  some  division  of  the  graduated 
neck;  this  reading,  plus  20  cc,  is  the  volume  displaced  by  64 
grams  of  the  cement. 


e;ngine:e;ring  chemistry  211 

13.  The  specific  gravity  is  then  obtained  from  the  formula, 
weight  of  cement,  in  grams, 


Specific  gravity 


displaced  vOiUme  in  cubic  centimeter 


14.  The  flask,  during  the  operation,  is  kept  immersed  in  water 
in  a  jar  (A),  in  order  to  avoid  variations  in  the  temperature  of 
the  liquid  in  the  flask,  which  should  not  exceed  ^°  C.  The 
results  of  repeated  tests  should  agree  within  o.oi.  The  deter- 
mination of  specific  gravity  should  be  made  on  the  cement  as 
received;  if  it  should  fall  below  3.10,  a  second  determination 
should  be  made  after  igniting  the  sample  in  a  covered  dish, 
preferably  of  platinum,  at  a  low  red  heat  not  exceeding  900°  C. 
The  sample  should  be  heated  for  5  minutes  with  a  Bunsen  burner 
(starting  with  a  low  flame  and  gradually  increasing  to  its  full 
height)  and  then  heated  for  15  minutes  with  a  blast  lamp;  the 
ignition  should  preferably  be  made  in  a  muffle-. 

15.  The  apparatus  may  be  cleaned  in  the  following  manner: 
The  fiask  is  inverted  and  shaken  vertically  until  the  liquid  flows 
freely,  and  then  held  in  a  vertical  position  until  empty ;  any  traces 
of  cement  remaining  can  be  removed  by  pouring  into  the  flask  a 
small  quantity  of  clean  liquid  benzene  or  kerosene  and  repeating 
the  operation. 

Fineness. 

16.  Significance. — It  is  generally  accepted  that  the  coarser  par- 
ticles in  cement  are  practically  inert,  and  it  is  only  the  extremely 
fine  powder  that  possesses  cementing  qualities.  The  more  finely 
cement  is  pulverized,  other  conditions  being  the  same,  the  more 
sand  it  will  carry  and  produce  a  mortar  of  a  given  strength. 

17.  Apparatus. — The  fineness  of  a  sample  of  cement  is  deter- 
mined by  weighing  the  residue  retained  on  certain  sieves.  Those 
known  as  No.  100  and  No.  200,  having  approximately  100  and 
200  wires  per  linear  inch,  respectively,  should  be  used.  They 
should  be  8  inches  in  diameter.  The  frame  should  be  of  brass, 
8  inches  in  diameter,  and  the  sieve  of  brass  wire  cloth  conform- 
ing to  the  following  requirements  : 


212 


ENGINE^^RIXG    CHEMISTRY 


No.  of  sieve 

Diameter  of  wire 
(inches) 

Meshes,  per  linear  inch 

Warp 

Woof 

lOO 
200 

0.0042  to  0.0048 
0.0021  to  0.0023 

95  to  lOI 
192  to  203 

92  to  103 
1 90  to  205 

The  meshes  in  any  smaller  space,  down  to  0.25  inch,  should  be 
proportional  in  number. 

18.  Method. — The  test  should  be  made  with  50  grams  of 
cement,  dried  at  a  temperature  of  100°  C.  (212°  F.). 

19.  The  cement  is  placed  on  the  No.  200  sieve,  which,  with 
pan  and  cover  attached,  is  held  in  one  hand  in  a  slightly  inclined 
position,  and  moved  forward  and  backward  about  200  times  per 
minute,  at  the  same  time  striking  the  side  gently,  on  the  up 
stroke,  against  the  palm  of  the  other  hand.  The  operation  is 
continued  until  not  more  than  0.05  gram  will  pass  through  in 
I  minute.  The  residue  is  weighed,  then  placed  on  the  No.  icx) 
sieve,  and  the  operation  repeated.  The  work  may  be  expedited 
by  placing  in  the  sieve  a  few  large  steel  shot,  which  should  be 
removed  before  the  final  i  minute  of  sieving.  The  sieves  should 
be  thoroughly  dry  and  clean. 

NORMAI,  C0NSISTE:nCY. 

20.  Significance. — The  use  of  a  proper  percentage  of  water  in 
making  pastes^  and  mortars  for  the  various  tests  is  exceedingly 
important  and  affects  vitally  the  results  obtained. 

21.  The  amount  of  water,  expressed  in  percentage  by  weight 
of  the  dry  cement,  required  to  produce  a  paste  of  plasticity 
desired,  termed  "normal  consistency,"  should  be  determined  with 
the  Vicat  apparatus  in  the  following  manner : 

22.  Apparatus. — This  consists  of  a  frame  (A),  Fig.  23,  bear- 
ing a  movable  rod  {B),  weighing  300  grams,  one  end  (C)  being 
I  centimeter  in  diameter  for  a  distance  of  6  centimeters,  the  other 
having  a  removable  needle  (Z)),  i  millimeter  in  diameter,  6 
millimeters  long.     The  rod  is  reversible,  and  can  be  held  in  any 

^  The  term  "paste"  is  used  in  this  report  to  designate  a  mixture   of  cement  and 
water,  and  the  word  "mortar"  to  designate  a  mixture  of  cement,  sand  and  water. 


KNGINKKRING   CHE:m1STRY 


213 


desired  position  by  a  screw  (B),  and  has  midway  between  the 
ends  a  mark  (F)  which  moves  under  a  scale  (graduated  to  milh- 
meters)  attached  to  the  frame  (A).  The  paste  is  held  in  a 
conical,  hard-rubber  ring  (G),  y  centimeters  in  diameter  at  the 
base,  4  centimeters  high,  resting  on  a  glass  plate  (H)  about  10 
centimeters  square. 


\B 


9    9 
F 


^E 


Fig.  23. — Vicat  apparatus. 

23.  Method. — In  making  the  determination,  the  same  quantity 
of  cement  as  will  be  used  subsequently  for  each  batch  in  making 
the  test  pieces,  but  not  less  than  500  grams,  with  a  measured 
quantity  of  water,  is  kneaded  into  a  paste,  as  described  in  para- 
graph 45,  and  quickly  formed  into  a  ball  with  the  hands,  com- 


214 


^ENGINEERING    CHEMISTRY 


pleting  the  operation  by  tossing  it  six  times  from  one  hand  to  the 
other,  maintained  about  6  inches  apart;  the  ball  resting  in  the 
palm  of  one  hand  is  pressed  into  the  larger  end  of  the  rubber 
ring  held  in  the  other  hand,  completely  filling  the  ring  with  paste  ; 
the  excess  at  the  larger  end  is  then  removed  by  a  single  move- 
ment of  the  palm  of  the  hand;  the  ring  is  then  placed  on  its 
larger  end  on  a  glass  plate  and  the  excess  paste  at  the  smaller 
end  is  sliced  off  at  the  top  of  the  ring  by  a  single  oblique  stroke 
of  a  trowel  held  at  a  slight  angle  with  the  top  of  the  ring.  Dur- 
ing these  operations  care  must  be  taken  not  to  compress  the 
paste.  The  paste  confined  in  the  ring,  resting  on  the  plate,  is 
placed  under  the  rod,  the  larger  end  of  which  is  brought  in  con- 
tact with  the  surface  of  the  paste ;  the  scale  is  then  read,  and  the 
rod  quickly  released. 

24.  The  paste  is  of  normal  consistency  when  the  cylinder 
settles  to  a  point  10  millimeters  below  the  original  surface  in 
Yz  minute  after  being  released.  The  apparatus  must  be  free  from 
all  vibrations  during  the  test. 

25.  Trial  pastes  are  made  with  varying  percentages  of  water 
until  the  normal  consistency  is  obtained. 

26.  Having  determined  the  percentage  of  water  required  to 
produce  a  paste  of  normal  consistency,  the  percentage  required 
for  a  mortar  containing,  by  weight,  i  part  of  cement  to  3  parts 
of  standard  Ottawa  sand,  is  obtained  from  the  following  table, 
the  amount  being  a  percentage  of  the  combined  weight  of  the 
cement  and  sand. 


Percentage  of  Water  for  Standard  Mortars. 


One  cement. 

One  cement. 

I 

One  cement. 

Neat 

three  standard 

Neat 

three  standard 

i       Neat 

three  standard 

Ottawa  sand 

Ottawa  sand 

1 

Ottawa  sand 

15 

8.0 

i        ^3 

9-3 

31 

10.7 

16 

8.2 

24 

9-5 

32 

10.8 

17 

8.3 

25 

9-7 

33 

II. 0 

18 

8.5 

26 

9.8 

34 

II. 2 

19 

8.7 

27 

10. 0 

35 

11-3 

20 

8.8 

28 

10.2 

36 

11-5 

21 

9.0 

29 

10.3 

37 

II. 7 

22 

9.2 

30 

10.5 

38 

II. 8 

engineering  chemistry  21$ 

Time  oe  Setting. 
2y.  Significance. — The  object  of  this  test  is  to  determine  the 
time  which  elapses  from  the  moment  water  is  added  until  the 
paste  ceases  to  be  plastic  (called  the  "initial  set"),  and  also  the 
time  until  it  acquires  a  certain  degree  of  hardness  (called  the 
"final  set"  or  "hard  set").  The  former  is  the  more  important, 
since,  with  the  commencement  of  setting,  the  process  of  crys- 
tallization begins.  As  a  disturbance  of  this  process  may  produce 
a  loss  of  strength,  it  is  desirable  to  complete  the  operation  of 
mixing  or  molding  or  incorporating  the  mortar  into  the  work 
before  the  cement  begins  to  set. 

28.  Apparatus. — The  initial  and  final  set  should  be  determined 
with  the  Vicat  apparatus  described  in  paragraph  22. 

29.  Method. — A  paste  of  normal  consistency  is  molded  in  the 
hard-rubber  ring,  as  described  in  paragraph  23,  and  placed  under 
the  rod  (B),  the  smaller  end  of  which  is  then  carefully  brought 
in  contact  with  the  surface  of  the  paste,  and  the  rod  quickly 
released. 

30.  The  initial  set  is  said  to  have  occurred  when  the  needle 
ceases  to  pass  a  point  5  millimeters  above  the  glass  plate ;  and  the 
final  set,  when  the  needle  does  not  sink  visibly  into  the  paste. 

31.  The  test  pieces  should  be  kept  in  moist  air  during  the  test; 
this  may  be  accomplished  by  placing  them  on  a  rack  over  water 
contained  in  a  pan  and  covered  by  a  damp  cloth;  the  cloth  to  be 
kept  from  contact  with  them  by  means  of  a  wire  screen;  or  they 
may  be  stored  in  a  moist  box  or  closet. 

32.  Care  should  be  taken  to  keep  the  needle  clean,  as  the  col- 
lection of  cement  on  the  sides  of  the  needle  retards  the  penetra- 
tion, while  cement  on  the  point  may  increase  the  penetration. 

33.  The  time  of  setting  is  affected  not  only  by  the  percentage 
and  temperature  of  the  water  used  and  the  amount  of  kneading 
the  paste  receives,  but  by  the  temperature  and  humidity  of  the 
air,  and  its  determination  is,  therefore,  only  approximate. 

Standard  Sand. 

34.  The  sand  to  be  used  should  be  natural  sand  from  Ottawa, 
111.,  screened  to  pass  a  No.  20  sieve,  and  retained  on  a  No.  30 


2l6 


KNGINEERING   CHEMISTRY 


sieve.  The  sieves  should  be  at  least  8  inches  in  diameter;  the 
wire  cloth  should  be  of  brass  wire  and  should  conform  to  the 
following  requirements : 


No    of  sieve 

Diameter  of  wire 
(inches) 

Meshes,  per  I,inear  Inch 

Warp 

Woof 

20 
30 

0.016  to  o.ory 
o.oii  to  0.012 

19.5  to  20.5 
29-5  to  30.5 

19.0  to  21.0 
28.5  to  31.5 

Fig.  24.. — Details  for  Briquette. 


ENGINEERING   CHEMISTRY 


217 


Sand  which  has  passed  the  No.  20  sieve  is  standard  when  not 
more  than  5  grams  pass  the  No.  30  sieve  in  i  minute  of  contin- 
uous sifting  of  a  500-gram  sample.- 

Form  of  Test  Pieces. 

35.  For  tensile  tests  the  form  of  test  piece  shown  in  Fig.  24 
should  be  used. 

36.  For  compressive  tests,  2-inch  cubes  should  be  used. 

Molds. 

37.  The  molds  should  be  of  brass,  bronze,  or  other  non-cor- 
rodible  material,  and  should  have  sufficient  metal  in  the  sides  to 
prevent  spreading  during  molding. 

38.  Molds  may  be  either  single  or  gang  molds.  The  latter  are 
preferred  by  many.  If  used,  the  types  shown  in  Figs.  25  and  26 
are  recommended. 


/ 


Fig.   25. — Details   for  gang  mold. 


Fig.  26. — Mold  for  compression  test  pieces. 


39.  The  molds  should  be  wiped  with  an  oily  cloth  before  using. 


Mixing. 

40.  The  proportions  of  sand  and  cement  should  be  stated  by 
weight;  the  quantity  of  water  should  be  stated  as  a  percentage 
by  weight  of  the  dry  material. 

41.  The  metric  system  is  recommended  because  of  the  con- 
venient relation  of  the  gram  and  the  cubic  centimeter. 

^  This  sand  may  now  (1912)  be  obtained  from  the  Ottawa  Silica  Co.,  at  a  cost  of 
two  cents  per  pound,  f.  o.  b.  cars,   Ottawa,  111. 


2i8  e:nginee)ring  che:mistry 

42.  The  temperature  of  the  room  and  of  the  mixing  water 
should  be  maintained  as  nearly  as  practicable  at  21°  C.  (70°  F.). 

43.  The  quantity  of  material  to  be  mixed  at  one  time  depends 
on  the  number  of  test  pieces  to  be  made;  1,000  grams  is  a  con- 
venient quantity  to  mix  by  hand  methods. 

44.  The  Committee  has  investigated  the  various  mechanical 
mixing  machines  thus  far  devised,  but  cannot  recommend  any  of 
them  for  the  following  reasons:  (i)  the  tendency  of  most 
cement  is  to  "ball  up"  in  the  machine,  thereby  preventing  work- 
ing it  into  a  homogeneous  paste;  (2)  there  are  no  means  of 
ascertaining  when  the  mixing  is  complete  without  stopping  the 
machine;  and  (3)  it  is  difficult  to  keep  the  machine  clean. 

45.  Method. — The  material  is  weighed,  placed  on  a  non-absorb- 
ent surface  (preferably  plate  glass),  thoroughly  mixed  dry  if 
sand  be  used,  and  a  crater  formed  in  the  center,  into  which  the 
proper  percentage  of  clean  water  is  poured;  the  material  on  the 
outer  edge  is  turned  into  the  center  by  aid  of  a  trowel.  As 
soon  as  the  water  has  been  absorbed,  which  should  not  require 
more  than  i  minute  the  operation  is  completed  by  vigorously 
kneading  with  the  hands  for  i  minute.  During  the  operation 
the  hands  should  be  protected  by  rubber  gloves. 

M01.DING. 

46.  The  Committee  has  not  been  able  to  secure  satisfactory 
results  with  existing  molding  machines ;  the  operation  of  machine 
molding  is  very  slow;  and  is  not  practicable  with  pastes  or  mor- 
tars containing  as  large  percentages  of  water  as  herein  recom- 
mended. 

47.  Method. — Immediately  after  mixing,  the  paste  or  mortar 
is  placed  in  the  molds  with  the  hands,  pressed  in  firmly  with  the 
fingers,  and  smoothed  off  with  a  trowel  without  ramming.  The 
material  should  be  heaped  above  the  mold,  and,  in  smoothing  off, 
the  trowel  should  be  drawn  over  the  mold  in  such  a  manner  as 
to  exert  a  moderate  pressure  on  the  material.  The  mold  should 
then  be  turned  over  and  the  operation  of  heaping  and  smoothing 
off  repeated. 

48.  A  check  on  the  uniformity  of  mixing  and  molding  may  be 


ENGINEERING   CHEMISTRY  219 

afforded  by  weighing  the  test  pieces  on  removal  from  the  moist 
closet;  test  pieces  from  any  sample  which  vary  in  weight  more 
than  3  per  cent,  from  the  average  should  not  be  considered. 

Storage  oi^  the  Test  Pieces. 

49.  During  the  first  24  hours  after  molding,  the  test  pieces 
should  be  kept  in  moist  air  to  prevent  drying. 

50.  Two  methods  are  in  common  use  to  prevent  drying:  (i) 
covering  the  test  pieces  with  a  damp  cloth,  and  (2)  placing  them 
in  a  moist  closet.  The  use  of  the  damp  cloth,  as  usually  carried 
out,  is  objectionable,  because  the  cloth  may  dry  out  unequally  and 
in  consequence  the  test  pieces  will  not  all  be  subjected  to  the  same 
degree  of  moisture.  This  defect  may  be  remedied  to  some  ex- 
tent by  immersing  the  edges  of  the  cloth  in  water;  contact  be- 
tween the  cloth  and  the  test  pieces  should  be  prevented  by  means 
of  a  wire  screen,  or  some  similar  arrangement.  A  moist  closet 
is  so  much  more  effective  in  securing  uniformly  moist  air,  and  is 
so  easily  devised  and  so  inexpensive,  that  the  use  of  the  damp 
cloth  should  be  abandoned. 

51.  A  moist  closet  consists  of  a  soapstone  or  slate  box,  or  a 
wooden  box  lined  with  metal,  the  interior  surface  being  covered 
with  felt  or  broad  wicking  kept  wet,  the  bottom  of  the  box  being 
kept  covered  with  water.  The  interior  of  the  box  is  provided 
with  glass  shelves  on  which  to  place  the  test  pieces,  the  shelves 
being  so  arranged  that  they  may  be  withdrawn  readily. 

52.  After  24  hours  in  moist  air,  the  pieces  to  be  tested  after 
longer  periods  should  be  immersed  in  water  in  storage  tanks  or 
pans  made  of  non-corrodible  material. 

53.  The  air  and  water  in  the  moist  closet  and  the  water  in  the 
storage  tanks  should  be  maintained  as  nearly  as  practicable  at 
21°  C.  (70°  F.). 

TensiIvE  Strength. 

54.  The  tests  may  be  made  with  any  standard  machine. 

55.  The  clip  is  shown  in  Fig.  27.  It  must  be  made  accurately, 
the  pins  and  rollers  turned,  and  the  rollers  bored  slightly  larger 
than  the  pins  so  as  to  turn  easily.    There  should  be  a  slight  clear- 


220 


KNGINKERING   CHEMISTRY 


ance  at  each  end  of  the  roller,  and  the  pins  should  be  kept  prop- 
erly lubricated  and  free  from  grit.  The  clips  should  be  used 
without  cushioning  at  the  points  of  contact. 


W{ 


SECTION  A-B 

Roller  turned  and  accurately 

bored  to  easy  turning  fit 


Fig.  27. — Form  of  Clip. 


56.  Test  pieces  should  be  broken  as  soon  as  they  are  removed 
from  the  water.  Care  should  be  observed  in  centering  the  'test 
pieces  in  the  testing  machine,  as  cross  strains,  produced  by  im- 
perfect centering,  tend  to  lower  the  breaking  strength.  The  load 
should  not  be  applied  too  suddenly,  as  it  may  produce  vibration, 
the  shock  from  which  often  causes  the  test  pieces  to  break  before 
the  ultimate  strength  is  reached.     The  bearing  surfaces  of  the 


e;nginee;ring  chemistry 


221 


clips  and  test  pieces  must  be  kept  free  from  grains  of  sand  or 
dirt,  which  would  prevent  a  good  bearing.  The  load  should  be 
applied  at  the  rate  of  600  pounds  per  minute  The  average  of 
the  results  of  test  pieces  from  each  sample  should  be  taken 
as  the  test  of  the  sample.  Test  pieces  which  do  not  break  within 
34  inch  of  the  center,  or  are  otherwise  manifestly  faulty,  should 
be  excluded  in  determining  average  results. 


Fig.  28. — Riehle  U.   S.   Standard   1,000-pound  automatic  cement  heater. 

Description  and  Operation. 
It  is  composed  entirely  of  metal.     The  beam  is  brought  to  a 


222  e;nginee:ring  chemistry 

balance  by  pouring  shot  into  the  cone-shaped  bucket  on  the  left 
of  the  machine,  thus  counterbalancing  the  weight  on  the  right- 
hand  side  of  the  machine.  The  test  briquette  is  then  placed  in 
the  grips  and  by  means  of  the  handwheel  under  the  lower  grip, 
the  slack  is  taken  up.  A  piston  valve  (Patented  Nov.  8,  1904) 
in  the  bucket  is  then  lifted  by  throwing  the  latch  over  and  the 
shot  flows  out  of  the  bucket  causing  the  weight  to  overbalance  the 
bucket  and  load  thus  to  be  applied  to  the  specimen.  When  a 
sufficient  weight  of  shot  has  flowed  out  of  the  bucket,  the  un- 
balanced force  of  the  weight  is  sufficient  to  break  the  briquette, 
and  then  the  lightened  bucket  is  moved  upward  by  the  weight 
and  the  piston  valve  in  it  closed,  causing  the  flow  of  shot  to  cease. 
To  change  the  speed  of  the  test  the  flow  of  shot  can  be  regulated 
by  means  of  the  knurled  screw  at  top  of  the  piston  valve. 

The  weight  of  shot  which  has  flowed  out  is  a  measure  of  the 
force  required  to  break  the  briquette,  and  this  shot  is  caught  in 
a  scoop  on  a  scale  which  is  graduated  to  read  directly  the  stress 
on  the  briquette. 

If  for  any  reason  the  main  beam  should  touch  the  buffer  before 
the  specimen  of  cement  is  broken,  the  valve  automatically  closes 
and  the  flow  of  shot  ceases.  The  operator  then  raises  the  beam 
by  means  of  the  crank  through  the  worm  and  worm  gear,  and 
the  test  continues. 

If  it  is  desired  to  make  a  test  with  the  beam  in  a  horizontal 
position,  it  can  be  kept  level  by  means  of  the  crank  and  worm 
wheel. 

In  place  of  the  spring  balance,  any  form  of  scale  may  be  used. 

Dimensions. 

Extreme  length    30  in. 

Extreme  width  15  in. 

Extreme  height  2  ft.  4  in. 

Weight   115  lbs. 

Shipping  weight   1 50  lbs. 

Shipping  measurements   10  cu.  ft. 

Compressive:  Strength. 
57.  The  tests  may  be  made  with  any  machine  provided  w4th 


Engine:rring  chemistry 


223 


means  for  so  applying  the  load  that  the  line  of  pressure  is  along 
the  axis  of  the  test  piece.  A  ball-bearing  block  for  this  purpose 
is  shown  in  Fig.  29.  Some  appliance  should  be  provided  to 
facilitate  placing  the  axis  of  the  test  piece  exactly  in  line  with 
the  center  of  the  ball-bearing. 


Fig.  29. — Ball-bearing  block  for  testing  machine'. 


58.  The  test  piece  should  be  placed  in  the  testing  machine, 
with  a  piece  of  heavy  blotting  paper  on  each  of  the  crushing 
faces,  which  should  be  those  that  were  in  contact  with  the  mold. 

Constancy  of  Voi^umf. 

59.  Significance. — The  object  is  to  detect  those  qualities  which 
tend  to  destroy  the  strength  and  durability  of  a  cement.  Under 
normal    conditions    these    defects    will    in    some    cases    develop 


224  ENGINEERING   CHEMISTRY 

quickly,  and  in  other  cases  may  not  develop  for  a  considerable 
time.  Since  the  detection  of  these  destructive  qualities  before 
using  the  cement  in  construction  is  essential,  tests  are  made  not 
only  under  normal  conditions  but  under  artificial  conditions 
created  to  hasten  the  development  of  these  defects.  Tests  may, 
therefore,  be  divided  into  two  classes  :  ( i )  Normal  tests,  made 
in  either  air  or  water  maintained,  as  nearly  as  practicable,  at  21° 
C.  (70°  F.)  ;  and  (2)  Accelerated  tests,  made  in  air,  steam  or 
water,  at  temperature  of  45°  C.  (113°  F.)  and  upward.  The 
committee  recommends  that  these  tests  be  made  in  the  following 
riianner : 

60.  Methods. — Pats,  about  3  inches  in  diameter,  }^  inch  thick 
at  the  center,  and  tapering  to  a  thin  edge,  should  be  made  on 
clean  glass  plates  (about  4  inches  square)  from  cement  paste  of 
normal  consistency,  and  stored  in  a  moist  closet  for  24  hours. 

61.  Normal  Tests. — After  24  hours  in  the  moist  closet,  a  pat 
is  immersed  in  water  for  28  days  and  observed  at  intervals.  A 
similar  pat,  after  24  hours  in  the  moist  closet,  is  exposed  to  the 
air  for  28  days  or  more  and  observed  at  intervals. 

62.  Accelerated  Test. — After  24  hours  in  the  moist  closet,  a 
pat  is  placed  in  an  atmosphere  of  steam,  upon  a  wire  screen  i 
inch  above  boiling  water,  for  5  hours.  The  apparatus  should  be 
so  constructed  that  the  steam  will  escape  freely  and  atmospheric 
pressure  be  maintained.  Since  the  type  of  apparatus  used  has 
a  great  influence  on  the  results,  the  arrangement  shown  in  Fig. 
30  is  recommended. 

63.  Pats  which  remain  firm  and  hard  and  show  no  signs  of 
cracking,  distortion,  or  disintegration  are  said  to  be  "of  constant 
volume"  or  "sound." 

64.  Should  the  pat  leave  the  plate,  distortion  may  be  detected 
best  with  a  straight-edge  applied  to  the  surface  which  was  in 
contact  with  the  plate. 

65.  In  the  present  state  of  our  knowledge  it  cannot  be  said  that 
a  cement  which  fails  to  pass  the  accelerated  test  will  prove  de- 
fective in  the  work ;  nor  can  a  cement  be  considered  entirely  safe 
simply  because  it  has  passed  these  tests. 


Engine;e)ring  chemistry 


225 


15 


226  ENGINEERING   CHEMISTRY 

Interpretation  of  Results  of  Tests. ^ 

Chemicae. 

The  composition  of  normal  Portland  cement  has  been  the  sub- 
ject of  a  great  deal  of  investigation  and  it  can  be  said  that  the 
quantities  of  silica,  alumina,  oxide  of  iron,  lime,  magnesia,  and 
sulphuric  anhydride  can  vary  within  fairly  wide  limits  without 
materially  affecting  the  quality  of  the  material. 

A  normal  American  Portland  cement  which  meets  the  standard 
specifications  for  soundness,  setting  time  and  tensile  strength 
has  an  approximate  composition  within  the  following  limits : 

Per  cent. 

Silica    19-25 

Alumina   5-9 

Iron  oxide  2-4 

Lime    60-64 

Magnesia    1-4 

Sulphur  trioxide   I-I-75 

Loss  on  ignition  0.5-3.00 

Insoluble  residue  o.  i-i  .00 

It  is  also  true  that  a  number  of  cements  have  been  made  both 
here  and  abroad  which  have  passed  all  standard  physical  tests 
in  which  these  limits  have  been  exceeded  in  one  or  more  par- 
ticulars, and  it  is  equally  true  that  a  sound  and  satisfactory 
cement  does  not  necessarily  resiilt  from  the  above  composition. 

It  is  probable  that  further  investigation  will  give  a  clearer 
understanding  of  the  constitution  of  Portland  cement,  but  at 
present  chemical  analysis  furnishes  but  little  indication  of  the 
quality  of  the  material. 

Defective  cement  usually  results  from  imperfect  manufacture, 
not  from  faulty  composition.  Cement  made  from  very  finely 
ground  material,  thoroughly  mixed  and  properly  burned,  may  be 
perfectly  sound  when  containing  more  than  the  usual  quantity  of 
lime,  while  a  cement  low  in  lime  may  be  entirely  unsound  due 
to  careless  manufacture. 

The  analysis  of  a  cement  will  show  the  uniformity  in  compo- 
sition of  the  product  from  individual  mills,  but  will  furnish  little 

^  United  States  Government  Specifications  for  Portland  Cement,  Circular  No.   33, 
Bureau  of  Standards,  May   i,    19 12. 


ENGINEERING   CHEMISTRY  227 

or  no  indication  of  the  quality  of  the  material.  Occasional  analy- 
sis should,  however,  be  made  for  record  and  to  determine  the 
quantity  of  sulphuric  anhydride  and  magnesia  present. 

The  ground  clinker  as  it  comes  from  the  mill  is  usually  quick 
setting  which  requires  correction.  This  is  usually  accomplished 
by  the  addition  of  a  small  quantity  of  more  or  less  hydrated 
calcium  sulphate,  either  gypsum  or  plaster  of  Paris.  Experience 
and  practice  have  shown  that  an  addition  of  3  per  cent,  or  less 
is  sufficient  for  the  purpose. 

Three  per  cent,  of  calcium  sulphate  (CaS04)  contains  about 
1.75  per  cent,  sulphuric  anhydride  (SO3),  and  as  this  has  been 
considered  the  maximum  quantity  necessary  to  control  time  of 
set,  the  specification  limits  the  SO3  content  to  1.75  per  cent. 

The  specification  prohibits  the  addition  of  any  material  sub- 
sequent to  calcination  except  the  3  per  cent,  of  calcium  sulphate 
permitted  to  regulate  time  of  set.  Other  additions  may  be  diffi- 
cult or  impossible  to  detect  even  by  a  careful  mill  inspection 
during  the  process  of  manufacture^  but  as  the  normal  adulterant 
would  be  ground  raw  material,  an  excess  of  "insoluble  residue" 
would  reveal  the  addition  of  silicious  material,  and  an  excess  in 
"loss  on  ignition"  would  point  to  the  addition  of  calcareous 
material  when  either  is  added  in  sufficient  quantity  to  make  the 
adulteration  profitable. 

The  effect  of  relatively  small  quantities  of  magnesia  (MgO) 
in  normal  Portland  cement,  while  still  vmder  investigation,  can 
be  considered  harmless.  Earlier  investigators  believed  that  as 
magnesia  had  a  slower  rate  of  hydration  than  lime,  the  hydration 
of  any  free  magnesia  (MgO)  present  would  occur  after  the 
cement  had  set  and  cause  disintegration. 

The  effect  of  magnesia  was  considered  especially  injurious 
when  the  cement  was  exposed  to  the  action  of  sea  water.  More 
recent  investigation  has  shown  that  cement  can  be  made  which  is 
perfectly  sound  under  all  conditions  when  containing  5  per  cent, 
of  magnesia  and  it  has  also  been  found  that  the  lime  in  Portland 
cement  exposed  to  sea  water  is  replaced  by  magnesia. 

The  maximum  limit  for  magnesia  has  been  set  at  4  per  cent., 


228  E;NGINE;e:rING    CHi^MISTRY 

as  it  has  been  established  that  this  quantity  is  not  injurious  and 
it  is  high  enough  to  permit  the  use  of  the  large  quantities  of  raw 
material  available  in  most  sections  of  the  country. 

Physicai.. 

Specific  Gravity. — If  the  Le  Chatelier  apparatus  is  used  for  the 
determination  of  specific  gravity,  the  clean  volumenometer  flask 
is  filled  with  benzene  free  from  water  (which  can  be  obtained 
by  placing  some  calcium  chloride  or  caustic  lime  in  the  benzene 
storage  jar)  to  a  point  on  the  stem  between  zero  and  i  cc. 
The  flask  is  then  placed  in  a  constant  temperature  bath 
until  volume  is  constant.  The  usual  method  is  to  introduce  64 
grams  of  cement  into  the  flask,  taking  care  that  the  powder  does 
not  adhere  to  the  tube  above  the  liquid,  and  to  free  the  cement 
from  air  by  rolling  the  flask  in  an  inclined  position.  The  flask 
is  then  replaced  in  the  constant  temperature  bath  until  a  constant 
volume  is  recorded. 

The  specific  gravity  is  obtained  from  the  formula : 

weight  of  cement  in  grams 

specific  gravity -p — ; -^ — ^ ■. —r^ . 

displaced  volume  in  cubic  centimeter 

The  specific  gravity  of  a  Portland  cement  is  not  an  indication 
of  its  cementing  value.  It  will  vary  with  the  constituents  of  the 
cement,  especially  with  the  content  of  iron  oxide.  Thus  the 
white  or  very  light  Portland  cements,  containing  a  fraction  of  a 
per  cent,  of  iron  oxide,  usually  have  a  comparatively  low  specific 
gravity  ranging  from  3.05  to  3.15,  while  a  cement  containing  3 
to  4  per  cent,  or  more  of  iron  oxide  may  have  a  specific  gravity 
of  3.20  or  even  higher.  It  is  materially  affected  by  the  temper- 
ature and  duration  of  burning  the  cement,  the  hard-burned 
cement  having  the  higher  specific  gravity.  A  comparatively  low 
specific  gravity  does  not  necessarily  indicate  that  a  cement  is 
underburned  or  adulterated,  as  large  percentages  of  raw 
materials  could  be  added  to  a  cement  with  a  normally  high 
specific  gravity  before  the  gravity  would  be  reduced  below  3.10. 

If  a  Portland  cement  fresh  from  the  mill  normally  has  a  com- 
paratively low  specific  gravity,  upon  aging  it  may  absorb  suf- 


ENGINEERING   CHEMISTRY  229 

ficient  moisture  and  carbon  dioxide  to  reduce  the  gravity  below 
3.10.  It  has  been  found  that  this  does  not  appreciably  affect  the 
cementing  value  of  the  material;  in  fact,  many  cements  are  un- 
sound until  th€y  have  been  aged.  Thus  a  redetermination  is 
permitted  upon  a  sample  heated  to  a  temperature  sufficient  to 
drive  off  any  moisture  which  may  be  absorbed  by  the  cement 
subsequent  to  manufacturing,  but  would  not  drive  off  any  car- 
bon dioxide  nor  correct  underburning  in  the  process  of  manu- 
facturing the  cement. 

The  value  of  the  specific  gravity  determination  lies  in  the  fact 
that  it  is  easily  made  in  the  field  or  laboratory,  and  when  the  nor- 
mal specific  gravity  of  the  cement  is  known,  any  considerable 
variation  in  quality  due  to  underburning  or  the  addition  of  for- 
eign materials  may  be  detected. 

Fineness. — Only  the  extremely  fine  powder  of  cement  called 
flour  possesses  appreciable  cementing  qualities  and  the  coarser 
particles  are  practically  inert.  No  sieve  is  fine  enough  to  deter- 
mine the  flour  in  a  cement,  nor  is  there  any  other  means  of  ac- 
curately and  practically  measuring  the  flour.  Some  cements 
grind  easier  than  others,  thus,  although  a  larger  percentage  of 
one  cement  may  pass  the  200-mesh  sieve  than  another,  the  for- 
mer may  have  a  smaller  percentage  of  actual  flour  due  to  the  dif- 
ference in  the  hardness  and  the  character  of  the  clinker,  and  the 
method  used  in  grinding.  Thus  the  cementing  value  of  different 
cements  can  not  be  compared  directly  upon  their  apparent  fine- 
ness through  a  200-mesh  sieve.  With  cement  from  the  same 
mill,  with  similar  clinker  and  grinding  machinery,  however,  it  is 
probable  that  the  greater  the  percentage  which  passes  the  200- 
mesh  sieve  the  greater  the  percentage  of  flour  in  that  particular 
cement. 

Normal  Consistency. — The  quantity  of  water  used  in  making 
the  paste  from  which  the  pats  for  soundness,  tests  of  setting,  and 
the  briquettes  are  made,  is  very  important  and  may  vitally  affect 
the  results  obtained.  The  determination  consists  in  measuring 
the  quantity  of  water  required  to  bring  a  cement,  to  a  certain 
state  of  plasticity. 


230 


ENGINEERING   CHEMISTRY 


In  determining  the  normal  consistency  by  the  ball  method, 
after  mixing  the  paste  it  should  be  formed  into  a  ball  with  as 
little  working  as  possible  and  a  new  batch  of  cement  should  be 
mixed  for  each  trial  paste.  In  order  to  obtain  just  the  requisite 
quantity  of  paste  to  form  a  ball  2  inches  in  diameter,  a  measure 
made  from  a  pipe  with  a  2-inch  inside  diameter  cut  i^  inches 


23.5  5^     ONE  PER  CENT.  ABOVE  NORMAL.  24.5$^     TWO  PER  CENT.  ABOVE  NORMAL 

Fig.   31. — Appearance  of  ball  for  different  consistencies  of  cement  paste. 

long  will  be  found  convenient.  The  section  of  pipe  should  be 
open  at  both  ends,  so  that  it  can  be  pushed  down  onto  the  paste 
on  the  mixing  table  and  the  excess  paste  cut  off  with  the  trowel. 
The  appearance  of  the  ball  using  the  correct  percentage  of  water 
for  normal  consistency  as  compared  with  a  less  and  greater 
quantity  of  water  is  shown  in  Fig.  31. 


ENGINEERING    CHEMISTRY  23I 

Mixing. — The  homogeneity  of  the  cement  paste  is  dependent 
upon  the  thoroughness  of  the  mixing,  and  this  may  have  con- 
siderable influence  upon  the  time  of  setting  and  the  strength  of 
the  briquettes. 

Soundness. — The  purpose  of  this  test  is  to  detect  those  qual- 
ities in  a  cement  which  tend  to  destroy  the  strength  and  dura- 
bility. Unsoundness  is  usually  manifested  by  a  change  in  vol- 
ume w^hich  causes  cracking,  swelling,  or  disintegration.  If  the 
pat  is  not  properly  made,  or  if  it  is  placed  where  it  will  be  subject 
to  any  drying  during  the  first  24  hours,  it  may  develop  what  are 
known   as   shrinkage   cracks,   which   are   not   an   indication   of 


32. — Soundness  pat  showing  Fig.  33. — Soundness  pat  showing 

shrinkage  cracks.  disintegration  cracks. 


Fig.   34. — Soundness  pat  with  top  surface  flattened 
for  determining  time  of  setting. 

unsoundness  and  should  not  be  confused  with  disintegration 
cracks,  as  shown  in  Figs.  32  and  33.  No  shrinkage  cracks  should 
develop  after  the  first  24  or  48  hours.  The  failure  of  the  pats  to 
remain  on  the  glass  nor  the  cracking  of  the  glass  to  which  the  pat 
is  attached  does  not  necessarily  indicate  unsoundness.  In  molding 
the  pats,  the  cement  paste  should  first  be  flattened  on  the  glass 
and  the  pat  formed  by  drawing  the  trowel  from  the  outer  edge 
toward  the  center,  as  shown  in  Fig.  35. 

Time  of  Setting. — The  purpose  of  this  test  is  to  determine  the 
time  which  elapses  from  the  moment  water  is  added  until  the 


232  ENGINEKRING   CHEMISTRY 

paste  ceases  to  be  plastic  and  the  time  required  for  it  to  obtain 
a  certain  degree  of  hardness.  The  determination  of  the  "initial 
set"  or  when  plasticity  ceases  is  the  more  important,  as  a  dis- 
turbance of  the  material  after  this  time  may  cause  a  loss  of 
strength  and  thus  it  is  important  that  the  mixing  and  molding  or 
the  incorporating  of  the  material  into  the  work  be  accomplished 
within  this  time.    The  time  of  setting  is  usually  determined  upon 


Fig-   35- — Correct   method  of  molding  cement  pat. 

one  of  the  pats  which  is  to  be  used  for  the  soundness  test,  the 
top  surface  being  flattened  somewhat,  as  shown  in  Fig.  34.  In 
using  the  Gillmore  needles  care  should  be  taken  to  apply  the 
needles  in  a  vertical  position  and  perpendicular  to  the  surface 
of  the  pat.  Fig.  36  shows  an  arrangement  for  mounting  the 
Gillmore  needles  so  that  they  are  always  perpendicular  to  the 
surface  of  the  pat.  The  rate  of  setting  and  hardening  may  be 
materially  affeted  by  slight  changes  in  temperature.  The  per- 
centage of  water  used  in  gauging  and  the  humidity  of  the  moist 


ENGINEERING   CHEMISTRY 


233 


closet  in  which  the  test  pieces  are  stored  may  also  affect  the 
setting  somewhat. 

Tensile  Tests. — Consistent  results  can  only  be  obtained  by 
exercising  great  care  in  molding  and  testing  the  briquettes.  The 
correct  method  of  filling  the  mold  is  shown  in  Figs.  37  and  38. 
In  testing,  the  sides  of  the  briquettes  and  the  clips  should  be 


-ci. 


3 


t'ig.  36, — Method  of  mounting  Gillmore  needles. 

thoroughly  cleaned  and  free  from  grains  of  sand  or  dirt  which 
would  prevent  a  good  bearing,  and  the  briquette  should  be  care- 
fully centered  in  the  clips  so  as  to  avoid  cross  strains.  It  may 
be  considered  good  laboratory  practice  if  the  individual  briquettes 
of  any  set  do  not  show  a  greater  variation  from  the  mean  value 
than  8  per  cent,  for  sand  mixtures  and  12  per  cent,  for  neat  mix- 
tures. 


234 


DNGINKKRING   CHEMISTRY 


Fig.   37. — Correct  method  of  filling  briquette  mold. 


Fig.  38. — Correct  method  of  troweling  surface  of  briquettes. 


E:NGlN]ei;RING   CHE)MISTRY  235 

Bureau  of  Standards,  Sieve  Specifications. 

Wire  cloth  for  standard  sieves  for  cement  and  sand  shall  be 
woven  (not  twilled)  from  brass,  bronze,  or  other  suitable  wire, 
and  mounted  on  the  frames  without  distortion. 

The  sieve  frames  shall  be  circular,  about  20  centimeters  (7.87 
inches)  in  diameter,  6  centimeters  (2.36  inches)  high,  and  pro- 
vided with  a  pan  about  5  centimeters  (1.97  inches)  deep  and  a 
cover. 

No.  100  Cement  Sieve,  o.oojj-Inch  Opening. — The  No.  100 
sieve  should  have  100  wires  per  inch  and  shall  conform  to  the 
following  specifications  of  diameter  of  wire  and  size  of  mesh : 

The  diameter  of  the  wires  in  the  sieve  should  be  0.0045  i'^ch 
and  the  average  diameter  of  such  wires  as  may  be  measured  shall 
not  be  outside  of  the  limits  0.0042  to  0.0048  inch  for  either  warp  or 
shoot  wires.  The  number  of  warp  wires  per  whole  inch,  as 
measured  at  any  point  of  the  sieve,  shall  not  be  outside  the  limits 
98  to  loi  per  inch,  and  of  the  shoot  wires  96  to  102  per  inch. 
For  any  interval  of  0.25  to  0.50  inch  in  which  the  mesh  may  be 
measured  the  mesh  shall  not  be  outside  the  limits  95  to  loi  wires 
per  inch  for  the  warp  wires  and  93  to  103  wires  per  inch  for  the 
shoot  wires. 

A^o.  200  Cement  Sieve,  0.002g-Inch  Opening. — The  No.  200 
sieve  should  have  200  wires  per  inch  and  shall  conform  to  the 
following  specifications  of  diameter  of  wire  and  size  of  mesh : 

The  diameter  of  the  wires  in  the  sieve  should  be  0.0021  inch, 
and  the  average  diameter  of  such  wires  as  may  be  measured 
shall  not  be  outside  the  limits  0.0019  to  0.0023  inch  for  either 
warp  or  shoot  wires.  The  number  of  warp  wires  per  whole 
inch,  as  measured  at  any  point  of  the  sieve,  shall  not  be  outside 
the  limits  195  to  202  per  inch,  and  of  the  shoot  wires  192  to  204 
per  inch.  For  any  interval  of  0.25  to  0.50  inch  in  which  the 
mesh  may  be  measured  the  mesh  shall  not  be  outside  the  limits 
192  to  203  wires  per  inch  for  the  warp  wires  and  190  to  205 
wires  per  inch  for  the  shoot  wires. 

No.  20  Sand  Sieve,  o.oj^^-Inch  Opening. — No.  20  sieves  shall 
have  between  19.5  and  20.5  wires  per  whole  inch  of  the  warp 


236  e:nginekring  chemistry 

wires  and  between  19  and  21  wires  per  inch  of  the  shoot  wires. 
The  diameter  of  the  wire  should  be  0.0165  inch  and  the  average 
as  measured  shall  not  vary  outside  the  limits  0.0160  to  0.0170 
inch. 

No.  JO  Sand  Sieve,  0.022^-Inch  Opening. — No.  30  sieves  shall 
have  between  29.5  and  30.5  wires  per  whole  inch  of  the  warp 
wires  and  between  28.5  and  31.5  per  whole  inch  of  the  shoot 
wires.  The  diameter  of  the  wire  should  be  o.oiio  inch  and  the 
average  as  measured  shall  not  vary  outside  the  limits  0.0105  to 
0.0115  inch. 

Chemical  Analyses. 

Reprint  of  Report  Authorized  by  the  Committee,  New  York  Section 
Society  for  Chemical  Industry. 

Solution. — One-half  gram  of  the  finely  powdered  substance  is 
to  be  weighed  out,  and,  if  a  limestone  or  unburned  mixture, 
strongly  ignited  in  a  covered  platinum  crucible  over  a  strong 
blast  for  15  minutes,  or  longer  if  the  blast  is  not  powerful  enough 
to  effect  complete  conversion  to  a  cement  in  this  time.  It  is  then 
transferred  to  an  evaporating  dish,  preferably  of  platinum  for 
the  sake  of  celerity  in  vaporation,  moistened  with  enough  water 
to  prevent  lumping,  and  5  to  10  cc.  of  strong  HCl  added  and 
digested  with  the  aid  of  gentle  heat  and  agitation  until  solution 
is  complete.  Solution  may  be  aided  by  light  pressure  with  the 
flattened  end  of  a  glass  rod.^  The  solution  is  then  evaporated  to 
dryness,  as  far  as  this  may  be  possible  on  the  bath. 

Silica  (SiO^). — The  residue  without  further  heating  is  treated 
at  first  with  5  to  10  cc.  of  strong  HCl  which  is  then  diluted  to 
half  strength  or  less,  or  upon  the  residue  may  be  poured  at  once 
a  larger  volume  of  acid  of  half  strength.  The  dish  is  then  cov- 
ered and  digestion  allowed  to  go  on  for  10  minutes  on  the  bath, 
after  which  the  solution  is  filtered  and  the  separated  silica  washed 
thoroughly  with  water.  The  filtrate  is  again  evaporated  to  dry- 
ness, the  residue  without  further  heating  taken  up  with  acid  and 
water  and  the  small  amount  of  silica  it  contains  separated  on  an- 

1  If  anything  remains  undecomposed  it  should  be  separated,  fused  with  a  little 
Na2C02,  dissolved  and  added  to  the  original  solution.  Of  course  a  small  amount  of 
separated  non-gelatinous  silica  is  not  to  be  mistaken  for  undecomposed  matter. 


ENGINEERING   CHEMISTRY  237 

other  filter  paper.  The  papers  containing  the  residue  are  trans- 
ferred wet  to  a  weighed  platinum  crucible,  dried,  ignited,  first 
over  a  Bunsen  burner  until  the  carbon  of  the  filter  is  completely 
consumed,  and  finally  over  the  blast  for  15  minutes  and  checked 
by  a  further  blasting  for  10  minutes  or  to  constant  weight.  The 
silica,  if  great  accuracy  is  desired,  is  treated  in  the  crucible  with 
about  10  cc.  of  HFl  and  4  drops  of  H0SO4,  and  evaporated  over 
a  low  flame  to  complete  dryness.  The  small  residue  is  finally 
blasted,  for  a  minute  or  two,  cooled  and  weighed.  The  difference 
between  this  weight  and  the  weight  previously  obtained  gives 
the  amount  of  silica.^ 

Alumina  and  Iron  {AIJD^  and  Fefi^). — The  filtrate  about 
250  cc.  from  the  second  evaporation  for  SiOg,  is  made  alkaline 
with  NH4OH  after  adding  HCl,  if  need  be,  to  insure  a  total  of 
10  to  15  cc.  strong  acid,  and  boiled  to  expel  excess  of  NH3,  or 
until  there  is  but  a  faint  odor  of  it,  and  the  precipitate  iron  and 
aluminum  hydrates,  after  settling,  are  washed  once  by  decantation 
and  slightly  on  the  filter.  Setting  aside  the  filtrate,  the  precipi- 
tate, is  dissolved  in  hot  dilute  HCl,  the  solution  passing  into  the 
beaker  in  which  the  precipitation  was  made.  The  aluminum  and 
iron  are  then  reprecipitated  by  NH^OH,  boiled  and  the  second 
precipitate  collected  and  washed  on  the  same  filter  used  in  the 
first  instance.  The  filter  paper,  with  the  precipitate,  is  then 
placed  in  a  weighed  platinum  crucible,  the  paper  burned  off  and 
the  precipitate  ignited  and  finally  blasted  5  minutes,  with  care  to 
prevent  reduction,  cooled  and  weighed  as  Al^Og  +  Fe203.^ 

Iron  {F^2^z)' — "^^^  combined  iron  and  aluminum  oxides  are 
fused  in  a  platinum  crucible  at  a  very  low  temperature  with  about 
3  to  4  grams  of  KHSO4,  or,  better,  NaHS04,  the  melt  taken  up 
with  so  much  dilute  H12SO4  that  there  shall  be  no  less  than  5 
grams  absolute  acid  and  enough  water  to  effect  solution  on  heat- 
ing. The  solution  is  then  evaporated  and  eventually  heated  till 
acid  fumes  come  off  copiously.  After  cooling  and  redissolving 
in  water  the  small  amount  of  silica  is  filtered  out,  weighed  and 

1  For.  ordinary  control  in  the  plant  laboratory  this  correction  may,  perhaps,  be 
neglected  ;  the  double  evaporation  never. 

'  This  precipitate  contains  TiOo,  P2O5,  Mn304. 


238  Engine:ering  che:mistry 

corrected  by  HFl  and  H,2S04/  The  filtrate  is  reduced  by  zinc, 
or  preferably  by  hydrogen  sulphide,  boiling  out  the  excess  of  the 
latter  afterwards  while  passing  CO2  through  the  flask,  and 
titrated  with  permanganate.^  The  strength  of  the  permanganate 
solution  should  not  be  greater  than  0.0040  gram  Fe^Og  per  cubic 
centimeter. 

Lime  (CaO). — To  the  combined  filtrate  from  the  AI2O3  + 
FcisOg  precipitate  a  few  drops  of  NH4OH  are  added,  and  the 
solution  brought  to  boiling.  To  the  boiling  solution  20  cc.  of  a 
saturated  solution  of  ammonium  oxalate  are  added,  and  the  boil- 
ing continued  until  the  precipitated  CaQ04  assumes  a  well- 
defined  granular  form.  It  is  then  allowed  to  stand  for  20  min- 
utes, or  until  the  precipitate  has  settled,  and  then  filtered  and 
washed.  The  precipitate  and  filter  are  placed  wet  in  a  platinum 
crucible,  and  the  paper  burned  off  over  a  small  flame  of  a  Bunsen 
burner.  It  is  then  ignited,  redissolved  in  HCl,  and  the  solution 
made  up  to  100  cc.  with  water.  Ammonia  is  added  in  slight 
excess,  and  the  liquid  is  boiled.  If  a  small  amount  of  AUOg 
separates  this  is  filtered  out,  weighed,  and  the  amount  added  to 
that  found  in  the  first  determination,  when  greater  accuracy  is 
desired.  The  lime  is  then  reprecipitated  by  ammonium  oxalate, 
allowed  to  stand  until  settled,  filtered  and  washed,^  weighed  as 
oxide  by  ignition  and  blasting  in  a  covered  crucible  to  constant 
weight,  or  determined  with  dilute  standard  permanganate.* 

Magnesia  (MgO). — The  combined  filtrates  from  the  calcium 
precipitates  are  acidified  with  HCl  and  concentrated  on  the 
steam  bath  to  about  150  cc,  10  cc.  of  saturated  solution  of 
Na  (HN4)HP04  are  added,  and  the  solution  boiled  for  several 
minutes.  It  is  then  removed  from  the  flame  and  cooled  by  plac- 
ing the  beaker  in  ice  water.     After  cooling,  NH4OH  is  added 

1  This  correction  of  Al203Fe203  for  silica  should  not  be  made  when  the  HFl  correction 
of  the  main  silica  has  been  omitted,  unless  that  silica  was  obtained  by  only  one  evapora- 
tion and  filtration.  After  two  evaporations  and  filtrations  i  to  2  milligrams  of  SiO  are 
still  to  be  found  with  the  AloOg  FcoOg. 

2  In  this  way  only  is  the  influence  of  titanium  to  be  avoided  and  a  correct  result 
obtained  for  iron. 

3  The  volume  of  wash-water  should  not  be  too  large  ;  vide  Hillebrand. 

*  The  accuracy  of  this  method  admits  of  criticism,  but  its  convenience  and  rapidity 
demand  its  insertion. 


e)ngine:e:ring  chemistry  239 

drop  by  drop  with  constant  stirring  until  the  crystalline  ammo- 
nium magnesium  orthophosphate  begins  to  form,  and  then  in 
moderate  excess,  the  stirring  being  continued  for  several  minutes. 
It  is  then  set  aside  for  several  hours  in  a  cool  atmosphere  and 
filtered.  The  precipitate  is  redissolved  in  hot  dilute  HCl,  the 
solution  made  up  to  about  100  cc,  i  cc.  of  a  saturated  solution 
of  Na  (NH4)HP04  added,  and  ammonia  drop  by  drop,  with 
constant  stirring  until  the  precipitate  is  again  formed  as  described 
and  the  ammonia  is  in  moderate  excess.  It  is  then  allowed  to 
stand  for  about  2  hours,  when  it  is  filtered  on  a  paper  or  a 
gooch  crucible,  ignited,  cooled  and  weighed  as  MgsPaO^. 

Alkalies  (K^^O  and  Na.fi). — For  the  determination  of  the 
alkalies,  the  well-known  method  of  Prof.  J.  Lawrence  Smith  is 
to  be  followed,  either  with  or  without  the  addition  of  CaCOg 
with  NH.Cl. 

Anhydrous  Sulphuric  Acid  (SO^). — One  gram  of  the  sub- 
stance is  dissolved  in  15  cc.  of  HCl,  filtered  and  residue  washed 
thoroughly.^ 

The  solution  is  made  up  to  250  cc.  in  a  beaker  and  boiled.  To 
the  boiling  solution  10  cc.  of  a  saturated  solution  of  BaCU  is 
added  slowly  drop  by  drop  from  a  pipette  and  the  boiling  con- 
tinued until  the  precipitate  is  well  formed,  or  digestion  on  the 
steam  bath  may  be  substituted  for  the  boiling.  It  is  then  set 
aside  over  night,  or  for  a  few  hours,  filtered,  ignited  and  weighed 
as  BaSO^. 

Total  Sulphur. — One  gram  of  the  material  is  weighed  out  in  a 
large  platinum  crucible  and  fused  with  NagCOg  and  a  little  KNO3, 
being  careful  to  avoid  contamination  from  sulphur  in  the  gases 
from  source  of  heat.  This  may  be  done  by  fitting  the  crucible 
in  a  hole  in  an  asbestos  board.  The  melt  is  treated  in  the  crucible 
with  boiling  water  and  the  liquid  poured  into  a  tall,  narrow  beaker 
and  more  hot  water  added  until  the  mass  is  disintegrated.  The 
solution  is  then  filtered.  The  filtrate  contained  in  a  No.  4  beaker 
is  to  be  acidulated  with  HCl  and  made  up  to  250  cc.  with  dis- 

^  Evaporation    to    dryness    is    unnecessary,    unless    gelatinous    silica    should    have 
separated  and  should  never  be  performed  on  a  bath  heated  by  gas;  vide  Hillebrand. 


240  ENGINEERING   CHEMISTRY 

tilled  water,  boiled,  the  sulphur  precipitated  as  BaS04,  and 
allowed  to  stand  over  night  or  for  a  few  hours. 

Loss  on  Ignition. — Half  a  gram  of  cement  is  to  be  weighed  out 
in  a  platinum  crucible,  placed  in  a  hole  in  an  asbestos  board  so 
that  about  three-fifths  of  the  crucible  projects  below,  and  blasted 
15  minutes,  preferably  with  an  inclined  flame.  The  loss  by 
weight,  which  is  checked  by  a  second  blasting  of  5  minutes,  is 
the  loss  on  ignition. 

May,  1903.- — Recent  investigations  have  shown  that  large  errors 
in  results  are  often  due  to  the  use  of  impure  distilled  water  and 
reagents.  The  analyst  should,  therefore,  test  his  distilled  water 
by  evaporation  and  his  reagents  by  appropriate  tests  before  pro- 
ceeding with  his  work. 

Specifications  for  Quicklime.^ 

1.  Quicklime  is  a  material  the  major  part  of  which  is  calcium  oxide 
or  calcium  and  magnesium  oxides,  which  will  slake  on  the  addition  of 
water. 

2.  Quicklime  is  divided  into  two  grades :' 

(a)  Selected — Shall  be   a   well-burned,   picked   free   from   ashes, 

core,  clinker  or  other  foreign  materials. 

(b)  Run-of-Kiln — Shall  be  a  well-burned  lime  without  selection. 

3.  Quicklime  is  shipped  in  two  forms : 

(a)  Lump  Lime — Shall  be  the  size  in  which  it  comes  from  the 

kiln. 
(6)  Pulverized  Lime — Shall   be   lump   limed   reduced   in   size   to 

pass  a  54-inch  screen. 

4.  Quicklimes  are  divided  according  to  their  chemical  composition 
into  four  types : 

(a)  High-Calcium — Shall    be   quicklime    containing    over   90   per 

cent,  of  calcium  oxide. 
{h)   Calcium — Shall  be  quicklime  containing  not  under  85  per  cent. 

and  not  over  90  per  cent,  of  calcium  oxide. 

(c)  Magnesium — Shall  be  quicklime  containing  between    10  and 

25  per  cent,  of  magnesium  oxide. 
{d)  Dolomitic — Shall  be  quicklime  containing  not  under  25  per 
cent,  of  magnesium  oxide. 

5.  The  particular  grade,  form  and  type  shall  be  specified  by  purchaser. 
^Tentative  Specifications,  Amer.  Soc.  Testing  Materials,   1914.  PP-   370-372. 


^NGINEEIRING   CHEMISTRY  24I 

I.   Chemical  Properties  and  Tests. 
(A)  Sampling. 

6.  When  quicklime  is  shipped  in  bulk,  the  sample  shall  be  so  taken 
that  it  will  represent  an  average  of  all  parts  of  the  shipment  from  top  to 
bottom,  and  shall  not  contain  a  disproportionate  share  of  the  top  and 
bottom  layers,  which  are  most  subject  to  changes.  The  samples  shall 
comprise  at  least  10  shovelfuls  taken  from  different  parts  of  the  ship- 
ment. The  total  sample  taken  shall  weigh  at  least  100  pounds  and  shall 
be  crushed  to  pass  a  i-inch  ring,  and  quartered  to  provide  a  15-pound 
sample  for  the  laboratory. 

7.  When  quicklime  is  shipped  in  barrels,  at  least  3  per  cent,  of  the 
number  of  barrels  shall  be  sampled.  They  shall  be  taken  from  various 
parts  of  the  shipment,  dumped,  mixed  and  sampled  as  specified  in  Sec- 
tion 6. 

8.  All  samples  to  be  sent  to  the  laboratory  shall  be  immediately 
transferred  to  an  air-tight  container  in  which  the  unused  portion  shall 
be  stored  until  the  quicklime  shall  finally  be  accepted  or  rejected  by  the 
purchaser. 

(J5)    Chemical  Tests. 

9.  (a)  The  grade,  type  and  chemical  properties  of  quicklime  shall  be 
determined  by  standard  chemical  methods  of  analysis. 

(b)  Selected  quicklime  shall  contain  not  under  90  per  cent,  of  calcium 
and  magnesium  oxides  and  not  over  3  per  cent,  of  carbon  dioxide. 

(c)  Run-of-kiln  quicklime  shall  contain  not  under  85  per  cent,  of 
calcium  and  magnesium  oxides,  and  not  over  5  per  cent,  of  carbon  dioxide. 

II.    Physical  Properties  and  Tests. 

10.  An  average  5-pound  sample  shall  be  put  into  a  box  and  slaked  by 
an  experienced  operator  with  sufficient  water  to  produce  the  maximum 
quantity  of  lime  putty,  care  being  taken  to  avoid  "burning"  or  "drowning" 
the  lime.  It  shall  be  allowed  to  stand  for  24  hours  and  then  washed 
through  a  20-mesh  sieve  by  a  stream  of  water  having  a  moderate  pres- 
sure. No  materials  shall  be  rubbed  through  the  screens.  Not  over 
3  per  cent,  of  the  weight  of  the  selected  quicklime  nor  over  5  per  cent, 
of  the  weight  of  the  run-of-kiln  quicklime  shall  be  retained  on  the  sieve. 
The  sample  of  lump  lime  taken  for  this  test  shall  be  broken  to  pass  a 
i-inch  screen  and  be  retained  on  a  ^-inch  screen. 

Pulverized  lime  shall  be  tested  as  received. 

III.    Inspection  and  Rejection. 

11.  (a)  All  quicklime  shall  be  subject  to  inspection. 

(b)   The  quicklime  may  be  inspected  either  at  the  place  of  manufac- 
ture or  the  point  of  delivery  as  arranged  at  the  time  of  purchase. 
16 


242  e:ngine:ering  chemistry 

(c)  The  inspector  representing  the  purchaser  shall  have  free  entry 
at  all  times  while  work  on  the  contract  of  the  purchaser  is  being  per- 
formed, to  all  parts  of  the  manufacturer's  w^orks  which  concern  the 
manufacture  of  the  quicklime  ordered. 

The  manufacturer  shall  afford  the  inspector  all  reasonable  facilities 
for  inspection  and  sampling,  which  shall  be  so  conducted  as  not  to  inter- 
fere unnecessarily  with  the  operation  of  the  works. 

(d)  The  purchaser  may  make  the  tests  to  govern  the  acceptance  or 
rejection  of  the  quicklime  in  his  own  laborator}^  or  elsewhere.  Such 
tests,  however,  shall  be  made  at  the  expense  of  the  purchaser. 

12.  Unless  otherwise  specified,  an}-  rejection  based  on  failure  to  pass 
tests  prescribed  in  these  specifications  shall  be  reported  within  5  days 
from  the  taking  of  the  samples. 

13.  Rehearing. — Samples  which  represent  rejected  quicklime  shall  be 
preserved  in  air-tight  containers  for  5  days  from  the  date  of  the  test 
report.  In  case  of  dissatisfaction  with  the  results  of  the  tests,  the  manu- 
facturer may  make  claim  for  a  rehearing  w'ithin  that  time. 


CONCRETE. 
Some  Field  and  Laboratory  Tests  of  Concrete.^ 

One  of  the  important  checks  instituted  within  the  past  year 
on  the  concrete  work  of  the  New  York  State  Highway  Commis- 
sion was  in  the  testing  of  the  finished  product.  Engineers  in 
charge  of  concrete  work  are  required  to  make  6-mch  cubes  from 
the  mixed  concrete  as  deposited  in  the  work.  Two  cubes  are 
taken  from  every  500  cubic  yards  of  concrete  laid;  this  in  the 
case  of  a  concrete  highway  16  feet  wide  and  of  our  standard 
thickness  represents  about  1,700  linear  feet  of  roadway.  These 
specimens  are  stored  in  moist  sand  near  the  highway  for  21  days 
at  which  time  they  are  sent  to  the  laboratory,  where  at  28  days 
they  are  tested  for  compressive  strength. 

Some  of  the  tests  so  made  are  tabulated  below.  Table  I  is  the 
record  of  some  very  high  compression  breaks  obtained  on  6-inch 
cubes  made  in  the  field  from  material  being  placed  on  the  high- 
way. There  is  some  slight  variation  in  the  age  of  the  different 
cubes  due  to  delay  in  shipping,  but  a  large  proportion  of  the 
material  is  from  28  to  30  days  old.    This  is  not  an  average  high- 

"^  Engineering  News,  Jan.  21,  1915,  by  H.  S.  Mattimore,  First  Assistant  Engineer, 
New  York   State  Highway   Commission,   Albany,   N.   Y. 


DNGINEE^RING   CHl^MISTRY  243 

way;  in  fact,  it  is  one  of  the  best.    The  two  interesting  features 


I 


Fig.    39. — Hydraulic   compression   machine   for   making   compression   tests   of 
Portland  cement  and  concrete  cubes. 

of  these  tests  are  the  consistent  uniformity  of  the  breaks  and  the 


244 


ENGINEERING   CHEMISTRY 


fact  that  the  compressions  are  the  highest  I  have  ever  seen  re- 
corded on  plain  concrete.  I  wish  to  call  attention  to  the  tests  on 
the  two  sands  from  different  banks,  used  in  this  concrete.  Both 
are  coarse  sands  with  voids  slightly  below  the  average,  they  are 
comparatively  clean  and  show  a  good  compressive  strength  in 
mortar.  They  would  not  be  called  sharp  sands  as  many  of  the 
grains  are  rounded.  This  material  is  from  an  old  lake  deposit 
and  unfortunately  rather  limited. 


4000 


CUBSS) 


?8D^YS 

Age   o-f    Concre+e 


6WEEKS 


Fig.  40. — Curves  showing  relative  compressive  strength  of  i:  1^:3  concrete 
using  different  aggregates.  (Six-inch  cubes  made  in  field  from  concrete 
being  used  in  highway  work  and  stored  in  field  21   days.) 

It  will  be  noted  the  last  two  cubes  tabulated  were  mixed  with 
stone  screenings  substituted  for  sand.  This  concrete  was  not 
used  in  the  highway,  but  was  made  for  experimental  purposes 
only.  It  may  be  rather  an  unfair  comparison  as  only  two  cubes 
were  made  from  this  material,  but  there  is  such  a  great  difference 
in  compressive  strength  that  we  do  feel  thankful  that  sand  rather 
than  stone  screenings  was  used  in  the  concrete  placed  in  the 
highway. 

The  curves  shown  in  the  accompanying  diagram  give  a  good 
illustration  of  concrete  obtained  in  acttial  practice.  I  believe  this 
is  a  good,  fair  comparison  of  stone  and  gravel  concrete,  as  both 
of  these  aggregates  were  of  high  grade,  particular  attention  being 
paid  to  obtain  a  clean,  uniform  product  passing  all  requirements 
for  this  class  of  concrete. 


ENGINEERING    CHEMISTRY 


245 


TABLE  I.— Compression  Tests  on  i  :  i>^  :  3  Concrete  Cubes,  Made 
From  Material  Being  Placed  on  N.  Y.  State  Highway. 


Break  lb.  per 

Break  lb.  per 

1 

Age 

sq.  in.,  aver, 
of  2  cubes 

Sand  used 

Age 

sq.  in.,  aver, 
of  2  cubes 

Sand  used 

30 

5480-;- 

33 

5555 -T- 

34 

4365 

'S 

28 

4500 

7 

45 

4«i5 

u 

28 

4680 

^ 

36 

3980 

n3 

28 

4050 

" 

28 

4810 

c 

30 

4665 

c 

29 

4925 

^ 

30 

4420 

S 

30 

4675 

'- 

28 

5030 

M 

28 

4625 

0 

28 

4450 

d 

28 

4875^ 

;?; 

32 

33 

4450 
1945* 

Z 

*  The  concrete  lepresented  by  the  last  two  cubes  was  made  of  stone  and  screenings 
substituted  for  sand.    It  was  made  for  experiment,  not  used  on  highway. 


Tests  of  Sand  Used 

IN  Above  Concrete. 

No.  I.  Voids  =  31.2  5< 
gradation  ;4 

Loam  =  1.5  ft 

compression 

break 

No.  2.  Voids  =  28.6  fo 
gradation  ^ 

Loam  =  2.5  ^i 

compression 

break 

Passing  %  in.        loo.o  ] 
Passing  No.      6,    93.3  | 
Passing  No.    20,    41.7  I 
Passing  No.    50,     10.5  [ 
Passing  No.  100,      1.8  j 
Passing  No.  200,      0.9  J 

I  :  3  Mortar 
Ottawa,  1420 
Natural, 

1987 
Washed, 

1802 

Passing  %  in.        loo.o ) 
Passing  No,      6,    94.0  | 
Passing  No.    20,    28.7  ! 
Passing  No.    50,      9-1  f 
Passing  No.  100,      1.6  | 
Passing  No.  200,      i.i  J 

I  :  3  Mortar 
Ottawa,  1520 
Natural, 

1750 
Washed, 

1685 

The  material  made  with  screenings,  although  show^ing  a  fair 
compression  strength,  is  much  below  that  obtained  with  a  good 
sand. 

In  Table  II  are  given  other  comparative  results  of  the  com- 
pressive strength  of  concrete  with  different  kinds  of  aggregate. 

TABLvE  II.— Comparative  Tests  on  1  :  2>^  :  5  Concrete  Using 

Different  Aggregates 

(6-in.  Cubes) 


Aggregates 


Slag  and  sand 

Stone  and  sand 

Gravel  and  sand 

Stone  and  screenings 

Coated  gravel  and  sand  unwashed 


Age 
Days 


28 
28 
28 
28 
28 


No.  of  cubes 


16 

134 

142 

28 

48 


Compression 
break,  lb. 
per  sq.  in. 


2,000 
1.990 

1.895 
1,740 
1,170 


246 


ENGINEERING   CHEMISTRY 


Table  III  is  given  to  show  the  importance  of  proper  sampHng 
of  sand  sources.  Both  of  these  sands  were  from  the  same  bank, 
being  sampled  by  different  engineers.  Sand  No.  i  is  well  within 
our  specifications  for  use  in  the  best  grade  of  concrete  while 
sand  No.  2  is  of  a  poor  grade  for  any  concrete. 


TABLE  III. — Table  to  Show  Effect  of  Sand  Gradation  on 
Compressive  Strength  of  Concrete. 


Gradation 


Passing    ^  in.   •    

Passing  No.      6 

Passing  No.     20 

Passing  No.    5C1 - 

Passing  No.  100 

Passing  No.  200 

Voids  per  cent.  

Loam  per  cent. 

Comparative  strength  (lb.  per  sq.  in.) 

Ottawa 

Natural 

Natural 

Ottawa  in  per  cent 


157-5 


No.   I 

No.  2 

per  cent. 

per  cent. 

1 00.0 

100. 0 

94 -o 

74-5 

38.4 

30-4 

14.4 

26.7 

2.0 

8.4 

1.4 

4.5 

30.9 

25-5 

3-6 

4.0 

1.445 

1.975 

2,275 

875 

44.2 


Specifications  for  Concrete  Pavement  and  Curb  Foundations. 

Bureau  of  Highways,  Borough  of  Manhattan,  N.  Y.,  1914. 
(Partial.) 

1.  Concrete  for  pavement  and  for  curb  foundations  shall  be  composed 
of  I  part  Portland  cement,  3  parts  of  sand  and  6  parts  of  broken  stone 
or  gravel,  or  a  mixture  of  both,  measured  by  volume.  For  the  purpose 
of  determining  these  proportions  i  bag  of  cement  shall  be  considered  a 
cubic  foot  and  the  other  materials  shall  be  measured  in  approved 
receptacles. 

2.  The  term  Portland  cement  shall  signify  the  finely  pulverized 
product  resulting  from  the  calcination  to  incipient  fusion  of  an  intimate 
mixture  of  properly  proportioned  argillaceous  and  calcareous  materials, 
and  to  which  no  addition  greater  than  3  per  cent,  has  been  made  subse- 
quent to  calcination. 

3.  It  shall  be  finely  ground,  of  uniform  color,  and  free  from  lumps 
and  cakes.  It  shall  weigh  not  less  than  380  pounds  to  the  barrel,  4  bags 
of  95  pounds  each,  being  considered  equivalent  to  i  barrel. 

4.  The  sample  shall  be  a  fair  average  of  the  contents  of  the  package 


e:ngine:e:ring  che:mistry  247 

taken  from  surface  to  center.  Samples  must  be  submitted  at  least  10  days 
(Sundays  and  holidays  excluded)  before  using,  for  the  inspection  and 
approval  of  the  engineer. 


15.  The  sand  shall  be  clean,  sharp,  free  from  dirt,  mica  and  vegetable 
matter,  and  shall  contain  not  more  than  5  per  cent,  of  clay.  It  shall  con- 
tain both  coarse  and  fine  particles  and  be  so  graded  that  not  more  than 
10  per  cent,  shall  be  retained  on  a  No.  4  sieve  and  all  retained  on  a  No.  100 
sieve.  Sand  which  does  not  fulfil  the  above  requirements  in  its  natural 
condition  shall  be  screened,  w^orked  or  mixed  with  other  sand  to  produce 
a  result  in  accordance  with  said  requirements. 

16.  If  approved  b}^  the  engineer  an  intimate  mixture  of  sand  and 
crusher  screenings  may  be  used  instead  of  sand  alone.  This  mixture  will 
generally  be  of  equal  parts,  though  the  proportions  of  screenings  to  sand 
may  be  materially  increased  at  the  discretion  of  the  engineer.  Crusher 
screenings  shall  be  free  from  dirt,  clay,  mica  and  vegetable  matter,  and 
all  shall  pass  a  No.  4  sieve  and  be  retained  on  a  No.  100  sieve. 

22.  The  concrete  foundation  shall  be  6  inches  thick,  unless  otherwise 
ordered  and  shall  withstand  such  tests  a^  may  be  deemed  necessary,  and 
the  contractor  shall  furnish  such  samples  as  may  be  required  for  the 
purpose. 

"Oil-mixed  Portland  cement  concrete"^  by  Logan  Waller  Page, 
Director,  Office  of  Public  Roads,  U.  S.  Dept.  of  Agriculture, 
gives  a  series  of  important  tests,  with  the  following  summary 
of  conclusions : 

( I ) .  The  tensile  strength  of  i  :  3  oil  mixed  mortar  is  very 
little  different  from  that  of  plain  mortar,  and  shows  a  substantial 
gain  in  strength  at  28  days  and  6  months  over  that  at  7  days. 

(2)  The  times  of  initial  and  final  set  are  delayed  by  the  addi- 
tion of  oil ;  5  per  cent,  of  oil  increases  the  time  of  initial  set  by 
50  per  cent,  and  the  time  of  final  set  by  47  per  cent. 

(3)  The  crushing  strength  of  mortar  and  concrete  is  decreased 
by  the  addition  of  oil  to  the  mix.  Concrete  with  10  per  cent,  of 
oil  has  75  per  cent,  of  the  strength  of  plain  concrete  at  28  days. 
At  the  age  of  i  year  the  crushing  strength  of  i  :  3  mortar  suffers 
but  little  with  the  addition  of  oil  in  amounts  up  to  10  per  cent. 

(4)  The  toughness  or  resistance  to  impact  is  but  slightly  af- 
fected by  the  addition  of  oil  in  amounts  up  to  about  10  per  cent. 

1  Office  of  Public  Roads,   Bulletin  No.  46,  U.    S.   Dept.  of  Agriculture. 


248 


ENGINEERING    CHEMISTRY 


Fig.  41. — Impact  test  on  oil-mixed  concrete. 


ENGINEERING   CHEMISTRY  249 

(5)  The  stiffness  of  oil-mixed  concrete  appears  to  be  but  little 
different  from  that  of  plain  concrete. 

(6)  Elasticity. — Results  of  tests  for  permanent  deformation 
indicate  that  no  definite  law  is  followed  by  oil  mixed  concrete. 

(7)  Absorption. — Oil  mixed  mortar  and  concrete  containing 
10  per  cent,  of  oil  have  very  little  absprption  and  under  low 
pressures  both  are  water-proof. 

(8)  Permeability. — Oil-mixed  mortar  containing  lo  per  cent, 
of  oil  is  absolutely  water-tight  under  pressures  as  high  as  40 
potmds  per  square  inch.  Tests  indicate  that  oil-mixed  mortar  is 
effective  as  a  waterproofing  agent  under  low  pressures  when 
plastered  on  either  side  of  porous  concrete. 

(9)  The  bond  tests  show  the  inadvisability  of  using  plain  bar 
reinforcement  with  oil-concrete  mixtures.  The  bond  of  de- 
formed bars  is  not  seriously  weakened  by  the  addition  of  oil  in 
amounts  up  to  10  per  cent. 

Note. — A  public  patent  has  been  granted  for  mixing  oil  with  Portland 
cement  concrete  and  hydraulic  cements  giving  an  alkaline  reaction,  and 
therefore  anyone  is  at  liberty  to  use  this  process  without  the  payment  of 
royalties. 

References. 

"Proportioning  Aggregates    for   Portland    Cement   Concrete,"   by  Albert 
Moyer,  Amer.  Society  Testing  Materials,  July,  1914. 
The  author  states  : 

"One  of  the  principal  results  obtained  in  these  investigations  was  that 
arbitrary  specifications  without  previous  knowledge  of  the  character  of 
the  aggregates  that  are  to  be  used  are  wrong,  and  that  such  stated  pro- 
portions as  1 :  2  :4  or  1 :3  :6,  etc.,  are  meaningless. 

"It  was  found  that  94  cubic  feet,  or  3.8  cubic  feet  per  barrel,  as  a  unit 
of  measurement  is  incorrect.  Investigations  prove  that  it  takes  no  pounds 
of  Portland  cement  to  make  i  cubic  foot  of  paste. 

"The  paper  gives  various  methods  of  carrying  on  investigations,  so 
that  with  a  given  sand  and  a  given  stone  or  gravel,  proportions  can  be 
stated  by  the  engineer  which  will  make  a  concrete  of  maximum  density 
and  maximum  strength." 
"Test  Results  with  Concrete  Water-proofing  Materials,"  Bng.  News,  Jan. 

21,  1915. 
"Standard    Practice    Instructions    for    Concrete    Testing    Laboratory,"    by 
Ralph   E.    Goodwin,   in   charge   of   tests   of   concrete   and   concrete 
aggregates.  Public  Service  Commission,  New  York  City,  Bng.  News, 
Feb.  4,  1915. 


250  ENGINEERING    CHEMISTRY 

ANALYSIS  OF  CLAY,  KAOLIN,  FIRE  SAND,  BUILDING 
STONES,  ETC. 

The  following  are  to  be  determined:  Silica  (total,  combined, 
free,  hydrated),  alumina,  lime,  magnesia,  potash,  soda,  ferrous 
or  ferric  oxide,  manganous  oxide,  titanic  oxide,  sulphur  trioxide, 
and  combined  water. 

The  total  silica  is  determined  by  fusing  i  gram  of  the  clay 
(previously  dried  at  100°  C.)  with  10  parts  of  an  equal  mixture 
of  sodium  and  potassium  carbonates,  in  a  large  platinum  cruci- 
ble. Fusion  must  be  complete  and  maintained  at  a  red  heat 
30  minutes. 

Allow  to  cool,  treat  with  an  excess  of  boiling  water,  make  acid 
with  hydrochloric  acid,  transfer  solution  to  a  4-inch  porcelain 
capsule  and  evaporate  to  dryness.  Take  up  with  25  cc.  hydro- 
chloric acid,  add  water,  boil,  and  filter  upon  ashless  filter.  Wash 
well  with  boiling  water,  dry,  ignite,  and  weigh  as  silica  (total). 

The  forms  of  combination  of  the  silica  in  the  clay  are  deter- 
mined as  follows  :^ 

Let  A  represent  silica  in  combination  with  bases  of  the  clay. 

Let  B  represent  hydrated  silicic  acid. 

Let  C  represent  quartz  sand. 

Dry  2  grams  of  the  clay  at  a  temperature  of  100°  C,  heat 
with  sulphuric  acid,  to  which  a  little  water  has  been  added,  for 
8  or  10  hours,  evaporate  to  dryness,  cool,  add  water,  filter  out 
the  undissolved  residue,  wash,  dry,  and  weigh  A  +  B  +  C. 
Now  transfer  it  in  small  portions  at  a  time  to  a  boilmg  solution 
of  sodium  carbonate  (i:  10)  contained  in  a  platinum  dish,  boil 
for  some  time,  filter  ofif  each  time,  still  very  hot.  When  all  is 
transferred  to  the  dish,  boil  repeatedly  with  strong  solution  of 
sodium  carbonate,  until  a  few  drops  of  the  fluid,  passing  through 
the  filter,  finally  remains  clear  on  warming-  with  ammonium 
chloride.  Wash  the  residue,  first  with  hot  water,  then  (to  in- 
sure the  removal  of  every  trace  of  sodium  carbonate  which  may 
still  adhere  to  it)  with  water  slightly  acidified  with  hydrochloric 
acid,  and  finally  with  w^ater.  This  will  dissolve  A  4-  B,  and 
leave  a  residue  C  of  sand,  which  dry,  ignite,  and  weigh. 

^  From   Fresenius'   "Quantitative   Analysis,"   Cairns,  p.   68. 


ENGINEERING    CHEMISTRY  2"^ 

To  determine  B,  boil  4  or  5  grams  of  the  clay  (previously 
dried  at  100°  C.)  directly  with  a  strong  solution  of  sodium 
carbonate,  in  a  platinum  dish  as  above,  and  filter  and  wash 
thoroughly  with  hot  water.  Acidify  the  filtrate  with  hydro- 
chloric acid,  evaporate  to  dryness  and  determine  this  silica.  It 
represents  B  or  the  hydrated  silicic  acid.  Add  together  the 
weights  of  B  and  C  thus  found  and  subtract  the  sum  from  the 
weight  of  the  first  residue  A  +  B  +  C.  The  difference  will 
be  the  weight  of  A  or  silica  in  combination  with  bases  in  the 
clay. 

If  the  weight  of  A  +  B  +  C  found  here  be  the  same  as  that 
of  the  silica  found  by  fusign,  in  another  sample  of  tlie  clay  of 
the  same  amount,  the  sand  is  quartz,  but  if  the  weight  of 
A  -f-  B  -f  C  be  greater,  then  the  sand  contains  silicates. 

The  weight  of  the  bases  combined  with  silica  to  silicates  can 
be  found  by  subtracting  the  weight  of  total  silica  found  in  i 
gram,  by  fusion,  from  the  weight  of  A  +  B  +  C  in  i  gram. 

Alumina,  Ferric  Oxide,  Manganese  Dioxide,  Lime,  and  Magnesia. 

The  hydrochloric  acid  filtrate  from  the  silica  (by  fusion)  is  made  nearly  alkaline  with 
sodium  carbonate,  then  excess  of  sodium  acetate  added,  the  solution  boiled  5  minutes 
then  filtered  bv  decantation  and  washed  well. 


Residue ,  AI2O3 .  Fe203 . 

Dissolve  in  hot  dilute 
H0SO4  and  divide  into 
two  equal  portions. 

First  Portion — Make 
alkaline  with  NH4OH 
boil  and  filter,  wash 
dry,  ignite,  and  weigh 
as  Al203.Feo03. 

Second  Portion'^— Ti 
trate  for  iron  calcu- 
late Feo  found  to  Fe203, 
and  this  subtracted 
from  weight  of  AloO;. 
l^'^sOs  gives  weight  of 
theAloOg. 

Both  weights  to  be 
multiplied  by  2. 


Filtrate, 

Transfer  to  a  flask,  add  a  few  drops  of   Br,  set  aside  12  hours, 
filter  and  wash. 


Residue,  MnOg. 

Dry,    ignite, 
weigh  as  Mn304 


and 


Filtrate. 

Add  a  few  drops  of  ammonia  (reaction  of 
solution  must  be  alkaline),  then  an  excess  of 
solution  of  ammonium  oxalate,  set  aside  4 
hours,  filter  and  wash. 


Residue,  CaC204. 

Dry.  ignite  and  weigh 
as  CaO. 


Filtrate. 

Add  solution  of  so- 
dium phosphate  with 
stirring,  set  aside  4 
hours,  fi  1  ter,  wash  with 
ammoniacal  water, dry 
and  ignite,  weigh  as 
Mg2P207,  and  calcu- 
late to  MgO. 


1  If  iron  is  present  in  small  amount,  fuse  3  grams  of  the  clav  with  Na2C03,  dissolve  in 
HoO,  acidify  with  HCl,  evaporate  to  dryness,  take  up  with  HCl.  precipitate  the  FejOg 
AI2O3  in  the  filtrate,  filter,  wash  precipitate  well  with  water,  dissolve  in  dilute  HJSO4, 
transfer  to  200  cc.  flask  with  Bunsen  valve,  reduce  with  zinc  and  titrate  with  standard 
permanganate  of  potash  solution. 


252  Engine:e:ring  che;mistry 

Potash  and  Soda. 

Take  i  gram  of  the  dried  clay,  transfer  to  a  3-inch  platinum 
capsule,  add  10  cc.  sulphuric  acid  and  20  cc.  hydrofluoric  acid 
and  heat  gently  until  the  silica  is  completely  vaporized  and  the 
excess  of  acid  added  driven  ofif.  Allow  to  cool,  add  20  cc.  warm 
hydrochloric  acid,  then  25  cc.  water,  transfer  contents  of  plati- 
num capsule  to  a  No.  3  beaker,  add  2  cc.  nitric  acid,  and  boil. 
Add  ammonia  to  alkaline  reaction,  boil,  filter  off  the  alumina  and 
ferric  oxide,  and  to  the  filtrate  add  ammonium  oxalate  to  precipi- 
tate the  lime;  allow  to  stand  4  hours,  then  filter;  the  magnesia 
is  separated  in  the  filtrate  by  ammonium  phosphate,  and  the  fil- 
trate from  the  magnesium  phosphate  precipitate  is  evaporated  to 
dryness  and  ignited  to  expel  ammonium  salts.  The  residue  is 
treated  with  hydrochloric  acid  and  the  potash  precipitated  by 
solution  of  platinic  chloride  as  usual,  and  weighed  as  KsPtClg  on 
counterpoised  filters.  The  alcoholic  washings  and  filtrate  are 
evaporated  to  dryness,  the  platinum  compound  decomposed  by 
heating  to  redness  with  oxalic  acid,  boiled  with  water,  filtered,  a 
few  drops  of  sulphuric  acid  added,  then  evaporated  to  dryness, 
ignited  to  constant  weight  as  sodium  sulphate,  and  then  cal- 
culated to  NagO. 

Sulphur  Trioxide. 

This  is  determined  by  fusing  i  gram  of  the  clay  with  sodium 
and  potassium  carbonates,  separating  the  silica  as  usual,  and 
precipitating  the  sulphur  trioxide  by  solution  of  barium  chloride 
in  the  acid  filtrate. 

Titanic  Oxide. 

Fuse  5  grams  of  the  dried  clay  with  an  excess  of  a  mixture  of 
sodium  fluoride  and  sodium  bisulphate,  in  a  platinum  crucible 
for  30  minutes  at  a  red  heat.  Treat  the  cold  mass  with  cold 
water,  about  200  cc,  add  potassium  hydroxide  in  excess,  filter 
off  the  titanic  oxide,  wash,  dry,  and  ignite  and  ftise  this  titanic 
oxide  with  about  twelve  times  its  weight  of  acid  sodium  sulphate; 
allow  to  cool,  and  treat  with  concentrated  sulphuric  acid.     This 


ENGINEERING   CHEMISTRY 


253 


is  now  added  to  600  cc.  of  water,  boiled  for  i  hour,  and  the 
precipitated  titanic  oxide  filtered,  dried,  and  weighed. 

Water  of  HydratioiL 

Take  2  grams  of  the  clay,  dried  at  100^  C,  transfer  to  a  cov- 
ered platinum  crucible  and  ignite  over  a  blast  lamp  at  a  red  heat 
to  constant  weight.    The  loss  represents  the  combined  w^ater. 
Composition  of  Some  Representative  Fire  Clays. 


SiOj  (com'd) 

A1,0, 

H,0  

KjO 

NajO 

CaO 

MgO 

Fe,0, 


SiOj  (freei  .- 

Moisture. 

TiO,.-... 

SO, 

Org.  matter  . 


50.46 
35-90 
12.74 


0.13 
0.02 
1-50 


Tot  a] 


50-15 
35-60 
13-61 

0.07 

O.Il 

0.16 

083 


0.14 


56.42 

26.35 

10-95 

0.48 

0.60 

055 

1-33 

2.80 
1.15 


65.10 

22.22 

7.10 

0.18 


0.14 
0.18 
1.92 

2.18 


058 


39-94 

36.30 

14.52 

0.42 

0.19 
0.19 
0.46 
4.90 
3.26 


0.72 

0.35 
0.14 

0.22 

0-18 
98-31 


40.33 

38.54 

13.00 

0.66 

0.08 
0.38 
0.90 
5-'5 


29.67 

20.87 

8.61 

1.55 


0.30 

1.45 
36.41 

1.14 


44.20 

39-14 

14-05 

0.25 


0.45 
0.20 
0.90 
1.05 


100.75100.67  100.63'  99.60    99. i&   99.92    99.24  ICO. 00  100.24 


Clays  or  fire  sands  that  are  to  be  used  in  the  manufacture  of 
fire-bricks,  retorts,  etc.,  should  contain  only  small  amounts  of 
easily  fusible  materials,  such  as  potash,  soda,  or  iron,  less  than 
I  per  cent,  of  either  alkali,  or  2  per  cent,  of  iron  oxide  being 
allowable  in  the  best  fire  clays. 

No.  I. — Mt.  Savage  fire  clay,  Md. 

Xo.  2. — Fire  clay,  Clearfield  County,  Pa. 

Xo.  3. — Glenboig  clay,  England. 

Xo.  4- — Stourbridge  clay,  England. 

Xo.  5. — Saaran  clay,  Germany. 

Xo.  6.— "Dinas,"  England.^ 

Xo.  7. — ^Zettlitz  clay,  Bohemia. 

Xo.  8- — Stoneware  clay,  X.  J. 

Xo.  9. — Paper  clay,  N.  J. 

*  Used  in  making  the  celebrated  "Dinas**  fire-bricks,  noted  for  their  endurance  at 
high  heats  and  for  swdUnc  and  making  ti^t  roofs  for  furnaces.. 


254 


ENGINEERING   CHEMISTRY 


Building  stone,  such  as  granite,  limestone,  sandstone,  slate, 
brick,  etc.,  are  generally  subjected  to  certain  mechanical  or  phys- 
ical tests  in  addition  to  a  chemical  analysis  to  determine  their 
relative  value. 

These  physical  tests  generally  comprise: 

1.  Crushing  strength. 

2.  Absorptive  power. 

3.  Resistance  to  the  expansion  of  frost,  by  saturating  the 

stone  with  water  and  freezing  a  number  of  times  to 
produce  an  effect  similar  to  frost. 

4.  Microscopical  examination. 

Crushing  Strength  of  Various  Building  Stones. 


Kind  of  stone. 


Granite 

Trap  rock  of  New  Jersey 

Marble 

Limestone 

Sandstone 

Common  red  brick  •  • . 


Ultimate  crushing  strength. 


Pounds  per  square  inch. 


Minimum. 


12,000 
20,000 
8,000 
7,000 
5,000 
2,000 


Maximum. 


21,000 
24,000 
20,000 
20,000 
15,000 
3,000 


Tons  per  .square  foot. 


860 
1,440 
580 
500 
360 
144 


Maximum. 


1,510 
1,730 
1,440 
1,440 
i,oSo 
216 


1.     Crushing  Strength. 

The  crushing  strength  is  generally  determined  by  applying  a 
measured  force  to  i-inch  or  2-inch  cubes  of  the  material  until 
they  are  crushed. 

These  compression  tests  are  comparative  only  and  give  no  idea 
of  the  crushing  strength  of  the  material  in  large  masses.  A 
Riehle  U.  S.  Standard  automatic  and  autographic  testing  machine 
is  used  for  this. purpose  (Fig.  42). 

In  the  specifications  for  granite  block  for  street  pavement,  the 
following  is  selected  as  a  portion  of  the  requirements : 

Quality. — The  granite  from  which  the  blocks  are  cut  shall  be  medium 
grained,  showing  uniformity  in  quality  and  texture,  without  seams,  scales 
or  discolorations  indicating  disintegration,  an  even  distribution  of  con- 
stituent minerals,  and  free  from  mica  or  feldspar.  No  outcrop,  soft, 
brittle  or  seamy  stones  will  be  accepted. 


i;ngine:e:ring  chemistry 


255 


Dimensions. — The  size  of  the  blocks  shall  be  as  follows:  Not  less 
than  6  inches  or  more  than  10  inches  long;  not  less  than  3^  inches  or 
more  than  4I/2  inches  wide,  and  not  less  than  4^4  inches  or  more  than 
5^  inches  deep. 


Inspection  before  Delivery. — The  paving  blocks  will  be  inspected  at 
the  quarry  or  at  the  dock  as  unloaded,  and  if  the  percentage  of  blocks 
failing  to  conform  to  these  specifications  found  in  1,000  blocks,  as 
unloaded,  shall  exceed  15  per  cent,  the  whole  cargo  will  be  condemned 
and  shall  not  be  used  on  the  work. 


256 


ENGINEERING   CHEMISTRY 


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I  ^^51. 


DNGINEKRING   CHEMISTRY 


257 


Compression  Test  of  Granite  Cxtbes. 


Designation 
of  specimen 

Dimension  specimen 

Crushing  load 

I^ength 
inches 

Width 
inches 

Breadth 
inches 

Area 
sq.  in. 

Actual 
lb. 

I^b.  per 
sq.  in. 

I.— w  

2.— W     

T              V 

1.97 
1.97 
1.98 
1.98 

1.968 
1. 961 
1.978 
1.967 

1. 961 
1.967 
I.97S 
1,980 

3.859 

3.857 
3.912 

3.895 

89,360 
100,000 

95,170 
100,000 

2.^,164 
25,930 
24.330 
25,670 

2.— Y 

2.    Absorptive  Power.^ 

This  is  determined  by  drying  the  sample  and  weighing  it,  then 
soaking  it  in  water  for  24  hours  and  weighing  again.  The 
increase  of  weight  represents  the  amount  of  water  absorbed.  A 
close,  fine-grained  stone  absorbs  less  water  than  a  coarse-grained 
one,  and  generally  the  less  the  absorption,  the  better  the  stone. 


Absorptive  Power  of  Stone,  Brick,  and  Mortar, 


Kind  of  material 


Granite  .  • 
Marble  .  . . 
Limestone 
Sandstone 
Brick  .... 
Mortar  •  .  • 


Rate  of  absorption 


Maximum 


Minimum 


I— 150 

0 

I-I50 

0 

1—20 

1-500 

I— 15 

1—240 

1-5 

1—50 

1  —  2 

I  — JO 

The  following  is  the  method  for  absorption  in  use  at  the  Road 
Material  Laboratory,  Bureau  of  Chemistry,  U.  S.  Dept.  of 
Agriculture:  The  method  used  for  determining  the  absorptive- 
ness  of  rock  is  not  intended  to  give  the  porosity,  but  merely  to 
obtain  the  number  of  pounds  of  water  absorbed  by  a  cubic  foot 
or  rock  in  96  hours,  determined  from  small  samples.  A 
smoothly  worn  stone,  between  20  and  60  grams  in  weight,  which 
has  been  through  the  abrasion  test  is  used.    Afte;r  being  weighed 


^  Thus,  if  150  units  of  dry  granite  weigh  after  immersion  in  water   151   units, 
absorption  is   i  in   150  stated   i — 150. 
17 


the 


258 


ENGINEJERING    CHE;MISTRY 


in  air  it  is  immersed  in  water  and  immediately  re-weighed  in 
water.    The  absorption  is  obtained  by  the  following  formula : 
Number  of  pounds  of  water  absorbed  by  a  cubic  foot  of  rock  zi: 
C  —  B 


A—  B 


X  62.5, 


in  which  A  is  equal  to  the  weight  in  air,  B  the  weight  in  water 
irnmediately  after  immersion,  C  the  weight  after  absorption  for 
96  hours,  and  62.5  the  weight  of  a  cubic  foot  of  water.  From 
these  weights,  the  specific  gravity  and  the  weight  per  cubic  foot 
of  the  rocks  are  determined.^ 

3.    Freezing  Test. 
Samples   of   the   weighed   material,   preferably   cut   in   2-inch 
cubes,  are  saturated  with  water,  then  placed  in  a  Tagliabue  freez- 


Fig-   43. 

ing   apparatus    (Fig.   43   and   maintained   at   a   temperature   of 

^  Transactions  American  Society  for   Testing  Materials,    1903,  p.   300. 


KNGINKERING   CHEMISTRY  259 

10°  F.  for  4  hours.  They  are  then  removed,  allowed  to  thaw 
gradually  to  a  temperature  of  about  65° ;  then  moistened  with 
water  and  placed  again  in  the  freezing  apparatus  and  maintained 
at  a  temperature  of  10°  F.  for  4  hours.  This  process  is  repeated 
at  least  ten  times,  when,  after  the  samples  have  acquired  the 
temperature  of  the  room,  the  moisture  is  wiped  from  them,  they 
are  then  dried,  and  their  weight  carefully  determined.  The  loss 
of  weight  represents  the  material  broken  off  by  the  expansive 
action  of  freezing  the  contained  water.  The  following  method 
of  making  the  frost  test  of  building  stones  is  from  "Uniform 
Methods  of  Procedure  in  Testing  Building  and  Structural 
Materials"  by  J.  Bauschinger  (Mechanisch-technischen  I^abora- 
torium,  Miinchen).^ 

The  examination  of  resistance  to  frost  is  to  be  determined 
from  samples  of  uniform  size,  inasmuch  as  the  absorption  of 
water  and  action  of  frost  are  directly  proportional  to  the  surface 
exposed.  The  test  sample  should  be  a  cube  of  7  centimeters 
(2.76  inches)  length  on  edges. 

The  frost  test  consists  of : 

a.  The  determination  of  the  compressive  strength  of  saturated 
stones,  and  its  comparison  with  that  of  dried  pieces. 

b.  The  determination  of  compressive  strength  of  the  dried 
stone  after  having  been  frozen  and  thawed  out  twenty-five  times, 
and  its  comparison  with  that  of  dried  pieces  not  so  treated. 

c.  The  determination  of  the  loss  of  weight  of  the  stone  after 
the  twenty-fifth  frost  and  thaw ;  special  attention  must  be  paid  to 
the  loss  of  those  particles  which  are  detached  by  the  mechanical 
action,  and  also  those  lost  by  solution  in  a  definite  quantity  of 
water. 

d.  The  examination  of  the  frozen  stone  by  use  of  a  magnify- 
ing glass,  to  determine  particularly  whether  fissures  or  scaling 
occurred. 

For  the  frost  test  are  to  be  used : 

Six  pieces  for  compression  tests  in  dry  condition,  three  normal 
and  parallel  to  the  bed  of  the  stone,  six  test  pieces  in  saturated 

^  Standard  Tests  and  Methods  of  Testing  Materials:    Trans.  Am.  Soc.  Mech.  Eng., 
14,   1294. 


26o  ENGINEERING   CHEMISTRY 

condition,  not  frozen,  however;  three  tested  normal  to,  and  three 
parallel  to,  bed  of  stone. 

Six  test  pieces  for  tests  when  frozen,  three  of  which  are  to  be 
tested  normal  to,  and  three  parallel  to,  bed  of  stone. 

When  making  the  freezing  test  the  following  details  are  to  be 
observed : 

a.  During  the  absorption  of  water,  the  cubes  are  at  first  to  be 
immersed  by  2  centimeters  (0.77  inch)  deep,  and  are  to  be  low- 
ered, little  by  little,  until  finally  submerged. 

h.  For  immersion  distilled  water  is  to  be  used  at  a  tempera- 
ture of  from  15°  to  20°  C. 

c.  The  standard  blocks  are  to  be  subjected  to  temperatures  of 
from  10°  to  15°  C. 

d.  The  blocks  are  to  be  subjected  to  the  influence  of  such  cold 
for  4  hours,  and  they  are  to  be  thus  treated  when  completely 
saturated. 

e.  The  blocks  are  to  be  thawed  out  in  a  given  quantity  of  dis- 
tilled water  at  from  15°  to  20°  C. 

The  Testing  of  Brick. — i.  When  testing  bricks  as  found  in  a 
delivery,  the  least  burnt  are  always  to  be  selected  for  investi- 
gation. 

2.  Bricks  are  to  be  tested  for  resistance  to  compression  in  the 
shape  of  cubical  pieces,  formed  by  the  superposition  of  two  half 
bricks,  which  are  to  be  united  by  a  thin  layer  of  mortar  consist- 
ing of  pure  Portland  cement,  and  the  pressure  surfaces  are  also 
to  be  made  smooth  by  covering  them  with  a  thin  coating  of  the 
same  material.    At  least  six  pieces  are  to  be  tested. 

3.  The  specific  gravity  is  to  be  determined. 

4.  In  order  to  control  the  uniformity  of  the  material,  the 
porosity  of  the  bricks  is  to  be  determined;  for  this  purpose  they 
are  to  be  thoroughly  dried  and  then  submerged  in  water  until 
saturated.  Ten  pieces  are  to  be  thoroughly  dried  upon  an  iron 
plate  and  weighed ;  then  these  bricks  are  to  be  immersed  in  water 
for  24  hours,  in  such  a  way  that  the  water-level  stands  at  half 
the  thickness;  after  this  they  are  to  be  submerged  for  another 
24  hours,  then  to  be  dried  superficially  and  again  weighed;  thus 


ENGINEERING   CHEMISTRY 


261 


the  average  quantity  of  water  absorbed  is  determined.  The 
porosity  is  always  to  be  calculated  by  volume,  though  the  per  cent, 
of  water  absorbed  is  always  to  be  stated  in  addition. 


Fig.   44. — Standard  automatic   transverse  brick   testing  machine. 

5.  Resistance  against  frost  is  to  be  determined  as  follows: 

a.  Five  of  the  bricks,  previously  saturated  by  water,  are  to  be 
tested  by  compression. 

b.  The  other  five  are  put  into  a  refrigerator  which  can  produce 
a  temperature  of  — 15°  C.  at  least,  and  kept  therein  for  4  hours; 
then  they  are  removed  and  thawed  in  water  of  a  temperature  of 
10°  C.  Particles  which  might  possibly  become  detached  are  to 
remain  in  the  vessels  in  which  the  brick  is  thawed  until  the  end 


262  ENGINEERING    CHEMISTRY 

of  the  Operation.  This  process  of  freezing  is  repeated  twenty- 
five  times,  and  the  detached  particles  are  dried  and  compared  by 
weight  with  the  original  dry  weight  of  brick.  Particular  atten- 
tion, by  using  a  magnifying  glass,  is  to  be  given  to  the  possible 
formation  of  cracks  or  laminations. 

c.  After  freezing,  the  bricks  are  to  be  tested  by  compression. 
For  this  test  they  are  dried,  and  the  result  obtained  is  to  be  com- 
pared with  that  of  dry  brick  not  frozen. 

d.  Thus,  freezing  the  bricks  does  not  give  a  knowledge  of  the 
absolute  frost-resisting  capacity;  the  value  of  the  investigation  is 
only  relative,  because  by  it  can  only  be  determined  which  brick 
can  be  most  easily  destroyed  by  the  action  of  frost. 

6.  To  test  bricks  for  the  presence  of  soluble  salts,  five  are 
selected,  and  again  those  which  are  least  burnt,  and  then  such 
which  have  not  yet  been  moistened.  Of  these,  again,  the  interior 
parts  only  are  used,  for  which  reason  the  bricks  are  split  in  three 
directions,  thus  producing  eight  pieces,  of  which  the  corners  lying 
innermost  in  the  brick  are  knocked  off.  These  are  then  powdered 
until  all  passes  through  a  sieve  of  900  meshes  per  square  centi- 
meter (about  5,840  per  square  inch),  from  which  the  dust  is  again 
separated  by  a  sieve  of  4,900  meshes  per  square  centimeter  (about 
31,360  per  square  inch),  and  the  particles  remaining  on  the  latter 
are  examined.  Twenty-five  grams  are  lixiviated  in  250  cc.  of 
the  distilled  water,  boiled  for  about  i  hour,  however,  replenishing 
the  quantity  of  water  evaporated,  then  filtered  and  washed. 

The  quantity  of  soluble  salts  present  is  then  determined  by 
boiling  down  the  solution  and  bringing  the  residue  to  a  red  heat 
for  a  few  minutes.  The  quantity  of  soluble  salts  present  is  to  be 
given  in  per  cent,  of  the  original  weight  of  brick. 

The  salts  obtained  are  to  be  submitted  to  a  chemical  analysis. 

7.  Determinations  of  the  presence  of  calcium  carbonate, 
pyrites,  mica,  and  similar  substances  are  to  be  made  on  the  un- 
burned  clay,  for  which  purpose  unburned  bricks  are  to  be  fur- 
nished. These  are  soaked  in  water  and  the  coarse  particles  are 
separated  by  passing  the  whole  material  through  a  sieve  having 
400  meshes  per  square  centimeter.    The  sand  thus  obtained  is  to 


ENGINEEIRING   CHEMISTRY  263 

be  examined  by  the  magnifying  glass  and  with  hydrochloric  acid 
to  determine  its  mineralogical  composition.  When  impurities, 
such  as  carbonate,  pyrites,  etc.,  are  found,  then  pieces  of  brick, 
such,  for  instance,  as  remained  from  the  determination  of  soluble 
salts,  are  to  be  examined  in  a  Papin's  digester  for  their  detele- 
rious  influence.  They  are  to  be  so  arranged  in  a  Papin's  digester 
that  they  are  not  touched  by  the  water  directly,  but  are  subjected 
to  the  action  of  the  generated  steam  alone.  The  pressure  of 
steam  shall  be  ^  atmosphere,  and  the  duration  of  test  3  hours. 
Possibly  occurring  disintegration  is  to  be  determined  by  means 
of  the  magnifying  glass. 

4.     Microscopical  Examination. 

This  consists  in  examining  under  the  microscope  thin  sections 
of  the  building  stone.  Important  results  are  often  obtained, 
especially  so  if  the  substances  used  as  matrix  are  indicated — the 
presence  and  amount  of  injurious  substances,  such  as  iron 
pyrites,  mica,  etc. 

Nearly  all  reports  upon  samples  of  building  stone  now  in- 
clude the  microscopical  examination. 

The  first  and  most  essential  test  applied  to  building  stone  is 
to  determine  the  structure  and  character  of  a  stone,  to  know 
whether  it  be  of  granite,  syenite,  sandstone,  quartzite,  or  some- 
thing else.  Although  an  expert  can  usually  determine  at  a 
glance  to  which,  if  any,  of  these  groups  a  particular  stone  be- 
longs, it  is  frequently  possible  to  determine  the  precise  litholog- 
ical  character  only  by  a  microscopical  examination.  Thus,  for 
instance,  there  is  a  class  of  Cambrian  rocks  commonly  called 
Potsdam  sandstone,  that  are  not  sandstones  at  all,  but  are  hard, 
compact  rocks  known  as  quartzites,  which  have  been  derived 
from  sandstones  by  metamorphic  action.  The  essential  differ- 
ence between  a  sandstone  and  a  quartzite  lies  in  the  presence  of 
secondary  silica  between  the  quartz  granules  comprising  the 
latter ;  the  presence  of  this  secondary  silica  or  quartz  can  be  de- 
termined for  a  certainty  only  by  microscopical  means.  The 
microscope  is  not  only  useful  in  determining  the  structure  of  a 


264  ENGINEERING   CHEMISTRY 

stone,  but  it  has  even  greater  practical  value  in  making  it  pos- 
sible to  detect  the  presence  of  deleterious  substances,  such  as 
pyrite  and  marcasite,  or  other  minerals  whose  chemical  com- 
position is  effected  by  atmospheric  agencies  and  thus  exert  a  del- 
eterious effect  upon  the  stone. ^ 

The  Testing  of  Paving  Bricks. 

This  consists  in  the  following  tests: 

1.  Cross  breaking. 

2.  Crushing. 

3.  Impact  (the  rattler  test). 

4.  Absorption. 

5.  Chemical  analysis. 

1.    Cross  Breaking.^ 

1.  Support  the  brick  on  edge,  or  as  laid  in  a  pavement,  on  a 
hardened  steel  knife  rounded  longitudinally  to  the  radius  of  12 
inches,  and  traversely  to  the  radius  of  ji  inch,  and  bolted  in 
position  so  that  the  screw-span  of  6  inches  applied  to  load  in  the 
middle  of  the  top  shall  pass  through  the  steel  knife  edge,  straight, 
longitudinal,  and  rounded  transversely  to  a  radius  of  1/16  inch. 

2.  Apply  the  load  to  the  middle  of  the  top  face  through  a  har- 
dened steel  knife-edge,  straight,  longitudinally,  and  rounded 
transversely  to  a  radius  of  1/16  inch. 

3.  Apply  the  load  in  a  uniform  rate  of  increase  until  fracture 
ensues. 

4.  Complete  the  modulus  of  rupture  by  the  formula  F  =  ^       .^  in 

which  F  =  modulus  of  rupture  in  pounds  per  square  inch ;  W  = 
the  total  brick  load  in  pounds ;  Iv  =  the  length  span  in  inches,  6 ; 
B  =  breadth  of  brick  in  inches;  D  =  depth  of  brick  in  inches. 

5.  Samples  for  test  must  be  free  from  all  visible  irregularities 
of  surface,  or  deformities  in  shape,  and  their  upper  and  lower 
faces  must  be  practically  parallel. 

^  H.  t,ynwood  Garrison;    Trans.  Amer.  Soc.   Civil  Eng.,  33,  88. 
2  "Street    Pavements    and    Paving    Materials,"   by    Geo.    W.    Tillson,    N.    Y,,    1900, 
p.  273. 


EJNGINDERING   CHEJMISTRY 


265 


6.  Not  less  than  10  bricks  shall  be  broken,  and  the  average  of 
all  is  to  be  taken  for  the  standard  test. 

2.    Crushing  Test. 

I.  The  crushing  test  should  be  made  of  half-brick  loaded  edge- 
wise, or  as  they  are  laid  on  the  street.  If  the  machine  used  is 
unable  to  crush  the  full  half -brick,  the  area  may  be  reduced  by 
chipping  off,  keeping  the  form  of  the  piece  to  be  tested  as  nearly 
prismatic  as  possible.     A  machine  (Fig.  45)  of  at  least  100,000 


Fig.   45. — Standard  rattler. 

pounds  capacity  should  be  used  and  the  standard  should  not  be 
reduced  below  4  square  inches  area  in  cross-section  at  right 
angles  to  direction  of  load. 

2.  The  upper  and  lower  surfaces  should  preferably  be  ground 
to  true  and  parallel  planes.  If  this  is  not  done,  they  should  be 
bedded  in  plaster  of  Paris  while  in  the  testing-machine,  and 
should  be  allowed  to  harden  10  minutes  under  weight  of  the 
crushing  plane  only  before  the  load  is  applied. 

3.  The  load  should  be  applied  at  a  uniform  rate  of  inrease  to 
the  point  of  rupture. 


266  ENGINEERING   CHEMISTRY 

4.  Not  less  than  the  average  obtained  from  five  tests  of  five 
different  bricks  shall  constitute  a  standard  test. 

3.    Impact  Test  (the  Rattler  Test). 

The  bricks  shall  not  lose  more  than  an  average  of  23  per  cent, 
in  abrasion  test  conducted  in  the  following  manner : 

1.  Standard  Rattler. — The  standard  shall  be  of  the  form  and 
dimensions  as  adopted  by  The  American  Society  for  Testing 
Materials,  1914. 

2.  Standard  Shot. — (Abrasive  Charge.)  The  abrasive  charge 
shall  consist  of  two  sizes  of  cast  iron  spheres.  The  larger  size 
shall  be  3.75  inches  in  diameter  when  new  and  shall  weigh  when 
new  approximately  7.5  pounds  (3.40  kilos)  each,  10  to  be  used. 

The  smaller  spheres  shall  be  when  new  1.875  inches  in  diam- 
eter and  shall  weigh  not  to  exceed  0.95  pound  (0.430  kilo) 
each.  Of  these  spheres  so  many  shall  be  used  as  will  bring  the 
collective  weight  of  the  large  and  small  spheres  most  nearly  to 
300  pounds. 

3.  The  Brick  Charge. — The  number  of  brick  per  charge  shall 
be  10  for  all  bricks  of  the  so-called  ''block-size"  whose  dimen- 
sions fall  between  from  8  to  9  inches  in  length,  3^4  inches  in 
breadth  and  334  and  4%  inches  in  thickness.  No  block  should 
be  selected  for  test  that  would  be  rejected  by  any  other  require- 
ments of  the  specifications. 

The  brick  shall  be  clean  and  dried  for  at  least  3  hours  in  a 
temperature  of  100°  F.,  before  testing. 

4.  Speed  and  Duration  of  Revolution. — The  rattler  shall  be 
rotated  at  a  uniform  rate  of  not  less  than  29^^  nor  more  than 
30^  revolutions  per  minute  and  1,800  revolutions  shall  consti- 
tute the  standard  test. 

A  counting  machine  shall  be  attached  to  the  rattler  for  count- 
ing the  revolutions.  A  margin  of  not  to  exceed  10  revolutions 
will  be  allowed  for  stopping.  Only  one  start  and  stop  per  test  is 
regular  and  acceptable. 

5.  The  Results. — The  loss  shall  be  calculated  in  percentage  of 
the  original  weight  of  the  dried  brick  composing  the  charge.     In 


e;ngine;e:ring  chicmistry 


267 


weighing  the  rattled  brick  any  piece  weighing  less  than  i  pound 
shall  be  rejected. 

All  bricks  must  give  modulus  of  rupture  of  not  less  than  1,800 
when  tested  on  their  sides,  being  supported  on  knife  edges  6 
inches  apart.  The  above  coefficients  to  be  calculated  by  the 
formula : 

3WL  ,.^ 


Modulus 


2AD 


in  which  W  equals  breaking  weight  at  the 


center ;  L  equals  length  between  supports ;  A  equals  area  section ; 
D  equals  depth. 

The  Board  reserves  the  right  to  accept  bids  on  bricks,  which 
have  successfully  passed  the  above  requirements  in  the  test  here- 
tofore referred  to,  made  under  their  direction. 

If  samples  are  submitted  on  other  bricks,  they  will  be  subject 
to  similar  comparative  tests  as  those  heretofore  mentioned,  and 
if  samples  do  not  meet  these  requirements,  bids  upon  such  bricks 
will  be  informal  and  not  considered. 

Fixing  of  Standards. — The  percentage  of  loss  which  may  be 
taken  as  the  standard  will  not  be  fixed  in  these  regulations,  and 
shall  remain  within  the  province  of  the  contracting  parties.  For 
the  information  of  the  public,  the  following  scale  of  average 
losses  is  given,  representing  what  may  be  expected  of  tests 
executed  under  the  foregoing  specifications. 


For  bricks  suitable  for  heavy  traffic. 
For  bricks  suitable  for  medium  traffic 
For  bricks  suitable  for  light  traffic  •  • 


Genera 
average 
loss 
(Per  cent.) 


24 
26 


Maximum 
permissible 

loss 
(Per  cent.) 


24 
26 
28 


which  of  these  grades  should  be  specified  in  any  given  district 
and  for  any  given  purpose  is  a  matter  wholly  within  the  province 
of  the  buyer,  and  should  be  governed  by  the  kind  and  amount 
of  traffic  to  be  carried,  and  the  quality  of  paving  bricks  available. 


Bulletin  23,  U.    S.   Department  of  Agriculture,   Slates. 


268  DNGINDERING   CHE:mISTRY 

4.    Absorption  Test. 

1.  Number  of  Brick. — The  number  of  brick  constituting  sam- 
ple of  the  official  test  shall  be  five. 

2.  Condition  of  the  Brick. — The  brick  selected  for  conducting 
this  test  shall  be  such  as  have  been  previously  exposed  to  the 
rattler  test.  If  such  are  not  available,  then  each  whole  brick 
must  be  broken  in  half  before  the  test  begins. 

3.  Drying. — The  brick  shall  be  dried  for  24  hours  continu- 
ously at  a  temperature  of  230°-250°  F.,  before  the  absorption. 

4.  Soaking. — The  brick  shall  be  weighed  before  wet,  and  shall 
then  be  completely  immersed  for  24  hours. 

5.  Wiping. — After  soaking,  and  before  reweighing,  the  bricks 
must  be  wiped  until  free  from  surplus  water  and  practically  dry 
on  the  surface. 

6.  Weighing. — The  samples  must  then  be  reweighed  at  once. 
The  scale  must  be  sensitive  to  i  gram. 

7.  Calculation  of  Result. — The  increase  in  weight  due  to  ab- 
sorption shall  be  calculated  in  per  cents,  of  the  dry  weight  of 
the  original  bricks. 

Standard  Abrasion  Test  for  Road  Material.^ 
This  well-known  test  is  similar  in  almost  all  respects  to  the 
Deval  abrasion  test  of  the  French  School  of  Road  and  Bridges. 
It  has  been  used  since  1878,  and  is  entirely  satisfactory  for  the 
purposes  for  which  it  was  designed. 

Abrasion  Test. 
The  machine  shall  consist  of  one  or  more  hollow  iron  cylin- 
ders; closed  at  one  end  and  furnished  with  a  tightly  fitting  iron 
cover  at  the  other ;  the  cylinders  to  be  20  centimeters  in  diameter 
and  34  centimeters  in  depth,  inside.  The  cylinders  are  to  be 
mounted  on  a  shaft  at  an  angle  of  30°  with  the  axis  of  rotations 
of  the  shaft. 

Standard  Abrasion  Cylinder  for  Road  Materials. 

At  least  30  pounds  of  coarsely  broken  stone  shall  be  available 
for  a  test.     The  rock  to  be  tested  shall  be  broken  in  pieces  as 

^  Adopted   1908,  Amer.   Soc.  Testing  Materials. 


e;ngine;e;ring  chejmistry  269 

nearly  uniform  in  size  as  possible,  and  as  nearly  50  pieces  as 
possible  shall  constitute  a  test  sample.  The  total  weight  of  rock 
in  a  test  shall  be  within  10  grams  of  5  kilograms.  All  test  pieces 
shall  be  washed  and  thoroughly  dried  before  weighing.  Ten 
thousand   revolutions,  at  the  rate  of  between  30  and  33   to  a 


Fig.  46. — Three  gang,  abrasion  cylinder,  belt  driven.     Weight,  480  pounds. 
Length,  7  feet.     Breadth,  30  inches.     Height,  34  inches. 

minute,  must  constitute  a  test.  Only  the  percentage  of  material 
worn  off  which  will  pass  through  a  0.16  centimeter  (i/i6-inch) 
mesh  sieve  shall  be  considered  in  determining  the  amount  of 
wear.  This  may  be  expressed  either  as  the  per  cent,  of  the  5 
kilograms  used  in  the  test,  or  the  French  coefficient,  which  is 
in  more  general  use,  may  be  given;  that  is,  coefficient  of  wear 

=  20  X  T^=   ~%Tr   "  W"  is  the  weight  in  grams  of  the  detritus 
W  W 

under  0.16  centimeter  (1/16  inch)  in  size  per  kilogram  of  rock 

used. 

Standard  Toughness  Test  for  Macadam  Rock.^ 

In  the  consideration  of  macadam  road  materials,  toughness  is 
understood  to  mean  the  power  possessed  by  a  material  to  resist 
fracture  by  impact. 

In  testing  macadam  rocks  under  impact,  it  has  been  found 
best  to  apply  a  number  of  blows  of  successively  increasing  energy 

2  Adopted   1908,  Amer.   Soc.  Testing  Materials. 


270 


^ngini:e:ring  chemistry 


and  note  the  blow  causing  failure.  The  following  test  involving 
this  principle  is,  therefore,  recommended  for  determining  the 
toughness  of  rock  for  macadam  road  building. 


Fig.   47. — Olsen  standard  impact  tester.      Length,   i   foot  9  inches.      Height,   s   feet 
8  inches.     Breadth,    11   inches.     Weight,  complete  with  motor,   250  pounds. 

Tough ne:ss  Test. 
I.  Test  pieces  may  be  either  cylinders  or  cubes,  25  millimeters 


ENGINEERING   CHEMISTRY  2^1 

in  diameter,  and  25  millimeters  in  height,  cut  perpendicular  to 
the  clearage  of  the  rock.  Cylinders  are  recommended  as  they 
are  cheaper  and  more  easily  made. 

2.  The  testing  machine  shall  consist  of  an  anvil  50  kilograms 
weight,  and  placed  on  a  concrete  foundation.  The  hammer  shall 
be  of  2  kilograms  weight,  and  dropped  upon  an  intervening 
plunger  of  i  kilogram  weight,  which  rests  on  the  test  piece. 
The  lower  or  bearing  surface  of  this  plunger  shall  be  of  spherical 
shape  having  a  radius  of  i  centimeter.  This  plunger  shall  be 
made  of  hardened  steel,  and  pressed  firmly  upon  the  test  piece 
by  suitable  springs.  The  test  piece  shall  be  adjusted,  so  that  the 
center  of  its  upper  surface  is  tangent  to  the  spherical  end  of  the 
plunger. 

3.  The  test  shall  consist  of  a  i  centimeter  fall  of  the  hammer 
for  the  first  blow,  and  an  increased  fall  of  i  centimeter  for  each 
succeeding  blow  until  failure  of  the  test  piece  occurs.  The  num- 
ber of  blows  necessary  to  destroy  the  test  piece  is  used  to  repre- 
sent the  toughness,  or  the  centimeter-gram  of  energy  applied 
may  be  used. 

Proposed  Definitions  of  Non-Bituminous  Road  Materials.^ 

Chert. — Compact    silicioiis    rock    formed    of    calcedonic   or   opaline   silica, 

or  both. 
Crusher-Run  Stone. — The  product  of  a  stone-crusher,  unscreened  except 

for  the  removal  of  the  particles  smaller  than  those  remaining  on  a 

0.32-centimeter  (^-inch)  screen. 
Dust. — Earth  or  other  matter  in  fine,  dry  particles,  so  attenuated  that  they 

can  be  raised  and  carried  by  the  wind.    The  product  of  a  rock  crusher 

passing  through  a  fine  screen. 
Flour. — Finely    ground    rocks    or    minerals    pulverized    to    an    impalpable 

powder. 
Granite. — A  granatoid  igneous  rock  consisting  of  quartz,  orthoclase,  more 

or  less  oligoclase,  biotite  and  muscovite. 
Granitoid. — A  textural  term  to  describe  those   igneous   rocks  which  are 

composed  of  recognizable  minerals. 
Matrix. — Material  used   to  bind   together   the   materials   in   agglomerated 

mass. 
Rubble. — Rough  stones  of  irregular  shapes  and  sizes,  broken  from  larger 

masses    either    naturally    or    artificially,    as    by    geological    action,    in 

quarrying,  or  in  stone-cutting  or  blasting. 

^  Amer.   Soc.  Testing  Materials,    19 14. 


272  ENGINEERING   CHEMISTRY 

Soil. — A  mixture  of  fine  earthy  material  with  more  or  less  organic  matter 

resulting  from  the  growth  and  decomposition  of  vegetation  or  animal 

matter. 
Spawl. — A  piece  of  rock  chipped  off  by  a  blow  of  a  hammer  or  other  tool. 
Stone  Chips. — Small  fragments  of  stone,  irregular  in  shape,  with  sharp 

edges,  containing  no  dust. 
Tailings. — Stones   which    after   going   through   the   crusher   do   not   pass 

through  the  largest  openings  of  the  screen. 

*  The  Determination  of  the  Apparent  Specific  Gravity  of  Rock.^ 

The  apparent  specific  gravity  of  rock  shall  be  determined  by  the  fol- 
lowing method:  First,  a  sample  weighing  between  29  and  31  grams  and 
approximately  cubical  in  shape  shall  be  dried  in  a  closed  oven  for  i  hour 
at  a  temperature  of  110°  C.  (230°  F.)  and  then  cooled  in  a  desiccator*  for 
I  hour;  second,  the  sample  shall  be  rapidly  weighed  in  air;  third,  trial 
weighings  in  air  and  in  water  of  another  sample  of  approximately  the 
same  size  shall  be  made  in  order  to  determine  the  approximate  loss  in 
weight  on  immersion;  fourth,  after  the  balances  shall  have  been  set  at 
the  calculated  weight,  the  first  sample  shall  be  weighed  as  quickly  as 
practicable  in  distilled  water  having  a  temperature  of  25°  C.  (77°  F.)  ; 
fifth,  the  apparent  specific  gravity  of  the  sample  shall  be  calculated  by 
the  following  formula : 

W 
Apparent   specific   gravity  =  —^ — — ' 

in  which  W  =  the  weight  in  grams  of  the  sample  in  air  and  Wi  =  the 
weight  in  grams  of  the  sample  in  water  just  after  immersion. 

Finally,  the  apparent  specific  gravity  of  the  rock  shall  be  the  average 
of  three  determinations,  made  on  three  different  samples  according  to  the 
method  above  described. 

The  Determination  of  the  Absorption  of  Water  per  Cubic  Foot 

of  Rock.2 

The  absorption  of  water  per  cubic  foot  of  rock  shall  be  determined 
by  the  following  method :  First,  a  sample  weighing  between  29  and  31 
grams  and  approximately  cubical  in  shape  shall  be  dried  in  a  closed  oven 
for  I  hour  at  a  temperature  of  110°  C.  (230°  F.)  and  then  cooled  in  a 
desiccator  for  i  hour;  second,  the  sample  shall  be  rapidly  weighed  in  air; 
third,  trial  weighings  in  air  and  in  water  of  another  sample  of  approxi- 
mately the  same  size  shall  be  made  in  order  to  determine  the  approximate 
loss  in  weight  on  immersion;  fourth,  after  the  balances  shall  have  been 
set  at  the  calculated  weight,  the  first  sample  shall  be  weighed  as  quickly 
as  possible  in  distilled  water  having  a  temperature  of  25°  C.  (77°  F.)  ; 
fifth,  allow  the  sample  to  remain  48  hours  in  distilled  water  maintained 

^Proposed   Provisional   Test,   Amer.    See.    Testing   Materials,    1914. 

*  Proposed   Provisional   Test,   Amer.    Soc.    Testing  Materials,    19 14. 


e:ngine:ering  chemistry  273 

as  nearly  as  practicable  at  25°  C.  {^TJ°  F.),  at  the  termination  of  which 
time  bring  the  water  to  exactly  this  temperature  and  weigh  the  sample 
while  immersed  in  it ;  sixth,  the  number  of  pounds  of  water  absorbed  per 
cubic  foot  of  the  sample  shall  be  calculated  by  the  following  formula : 

W..  —  W, 

Pounds  of  water  absorbed  per  cubic  foot  =  -—7 ~  X  62.24, 

W  —  Wi 

in  which  W  =  the  weight  in  grams  of  sample  in  air,  Wi  =  the  weight 

in  grams  of  sample  in  water  just  after  immersion,  W2  ^  the  weight  in 

grams   of   sample  in  water  after  48  hours   immersion,   and  62.24  1=  the 

weight  in  pounds  of  a  cubic  foot  of  distilled  water  having  a  temperature 

of  25°  C.  {If  F.). 

Finally,  the  absorption  of  water  per  cubic  foot  of  the  rock,  in  pounds, 

shall   be   the   average    of   three   determinations    made    on   three   different 

samples  according  to  the  method  above  described. 

Mechanical  Analysis  of  Broken  Stone  or  Broken  Slag.^ 

The  method  shall  consist  of,  first,  drying  at  not  exceeding  110°  C. 
(230°  F.)  to  a  constant  weight  a  sample  weighing  in  pounds  six  times 
the  diameter  in  inches  of  the  largest  holes  required ;  second,  passing  the 
sample  through  such  of  the  following  sized  screens  having  circular  open- 
ings as  are  required  or  called  for  by  the  specifications,  screens  to  be  used 
in  the  order  named:  8.89-centimeter  (3^-inch),  7.62-centimeter  (3-inch), 
6.35-centimeter  (2j/2-inch),  3.81-centimeter  (i^-inch),  3.18-centimeter 
(i^-inch),  2.54-centimeter  (i-inch),  1.90-centimeter  (^-inch),  1.27-centi- 
meter (^-inch),  and  0.64-centimeter  (54-inch)  ;  third,  determining  the 
percentages  by  weight  retained  on  each  screen;  fourth,  recording  the 
mechanical  analysis  in  the  following  manner : 

Percentage  passirlg  0.64-centimeter  (^-inch)  screen  = 
Percentage  passing  1.27-centimeter  (^-inch)  screen  =: 
Percentage  passing  1.90-centimeter  (^-inch)  screen  = 
Percentage  passing  2.54-centimeter     (i-inch)   screen  ■=:. 


100.00 


ASPHALT.2 

The  term  asphalt,  as  originally  applied,  represented  a  natural 
deposit  of  a  bituminous  substance  capable  of  extraction  from  the 
earth  in  the  condition  of  a  solid,  or  semi-solid  body  of  dark 
brownish  black  color  of  a  consistency  approaching  solid  pitch, 
and  capable  of  complete  combustion. 

^  Proposed  Provisional  Method,  Amer.   Sec.  Testing  Materials. 

^  "Asphalt,  its  Occurrence,  Composition,  and  Commercial  Uses,  with   Schemes  fof 
its  Analysis,"  by  Thos.  B.   Stillman,  Stevens  Institute  Indicator,  Oct.,   1904. 
18 


274 


.lENGIN^ERING   CHE:miSTRY 


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e:ngine:e;ring  chemistry 


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276  e;ngine:e)ring  che;mistry 

The  Latin  word  Asphaltum  is  probably  derived  from  the  Greek 
word  Aspholtos.  Homer  used  it  and  in  its  Latin  form  gave  the 
name  to  the  lake  of  Palestine,  known  as  the  Dead  Sea  {Locus  As- 
phalities)  and  anciently  as  the  source  of  the  bitumen,  called 
bitumen  judiacum.  Aristotle  called  it  Asphaltos  and  Xenophon 
400  B.  c,  describes  the  wall  of  Media  as  built  of  burnt  bricks 
laid  in  asphalt.  In  later  years  the  term  asphalt  and  bitumen  have 
been  used  rather  indiscriminately,  incurring  more  or  less  con- 
fusion in  the  literature  of  the  subject. 

This  asphalt  is  obtained  from  the  island  of  Trinidad  and  occurs 
in  two  characteristic  deposits. 

First,  the  lake  asphalt,  and,  second,  the  Trinidad  land  asphalt. 

The  difference  between  them  consists  in  the  fact  that  the  lake 
asphalt  contains  more  of  the  cementing  material  (petrolene)  than 
the  land  asphalt  which  contains  more  of  harder  bitumen  (asphal- 
tene) — and  also  more  earthy  matter. 

The  crude  Trinidad  asphaltum,  analyzed  in  my  laboratory,  gave 
the  following  result : 

Per  cent. 

^^^'o\en^  .    ^^^ 

Asphaltene  ) 

Organic   matter    . .   >  «  ^ 

Non-bituminous...    ^ 

Inorganic  residue    39-24 

Total 100.00 

The  following  analyses  were  made  by  Booth,  Garrett  and  Blair, 
consulting  chemists,  Philadelphia,  upon  various  asphalts.^ 

Trinidad  AvSphalt  (Refined). 

Specific  gravity    1.37 

Per  cent. 

Petrolene    70.12 

Asphaltene 25.13 

Retine  ( See  page  277) 3.25 

Non-bituminous        \ 

Organic  matter  )    ^ 

Total    100.00 

1  Report  to  the  Citizens'  Municipal  lycague,  Philadelphia. 


ENGINEERING   CHEMISTRY  277 

Bermudez  Asphalt  (Refined). 

Specific  gravity   1,09 

Per  cent. 

Petrolene    76.90 

Asphaltene     21,08 

Retine 1.02 

Non-bituminous        ^ 

Organic  matter          \    ^'^ 

Total   100.00 

Mexican  Asphalt  (Naturae  Deposit). 

Specific  gravity 1.06 

Per  cent. 

Petrolene   68.40 

Asphaltene 29.78 

Retine^    

Non-bituminous        ^ 

Organic  matter         \    • ^'^^ 

Total   100.00 

Uvalde  Asphalt   (Refined).^ 

Petrolene   71.78 

Asphaltene  28.01 

Non-bituminous        ^ 

Organic  matter         ^    '  ^'^^ 

Total 100.00 

Cuban  Asphalt. 

Petrolene   25.46 

Asphaltene     54-41 

Total  bitumen    79.87 

Mineral  matter 20.13 

Dead  Sea  Asphalt. 

Per  cent. 

Petrolene   3509 

Asphaltene     63.18 

Total  bitumen    ^,8.27 

Mineral  matter 1.73 

1  Retine  occurs  in  some  asphalts,  but  in  small  amounts  only,  soluble  in  alcohol.  Its 
composition  varies.  De  Smedt  gplves  its  formula  as  Ci  78.84  per  cent.,  Hj  19.22  per  cent., 
Si  10.78.    This  compound  is  not  desirable  in  asphalt. 

Consult:     Jour.    Franklin   Inst.,    1901,    p.    50;    Dana's    Mineralogy    (Retinellite), 
pp.  748-749. 

^  Analysis  made  in  the  chemical  laboratory  of  Stevens  Institute  of  Technology. 


278  ^NGINEJERING   CHE:mISTRY 

Rock  asphalts  and  sand  asphalts  usually  contain  but  small 
amounts  of  asphalt,  and  often  are  used  directly  for  street  pav- 
ing. The  celebrated  French  Val  de  Travers  Rock  Asphalt  con- 
tains as  follows : 

Per  cent. 

Petrolene   8.52 

Asphaltene 3.92 

Total  bitumen 12.44 

Mineral  matter    87.56 

Seyssei.  Rock  Asphai^t.^ 

Petrolene   7.48 

Asphaltene     4.32 

Total  bitumen    11.80 

Mineral  matter    88.20 

Utah  Asphai^t  Rock  (Limestone). 

Petrolene   31.20 

Asphaltene 12.60 

Total  bitumen    43.80 

Mineral  matter    56.20 

Caueornia  Sand-Rock  Asphalt. 

Petrolene   1 1.32 

Asphaltene 3.81 

Total  bitumen    15.13 

Mineral  matter    84.87 

Texas  Sand  Asphai,t  (Anderson  County). 

Petrolene   12.09 

Asphaltene 1 1.25 

Total  bitumen    23.34 

Mineral  matter    76.66 

From  the  Uvalde  bituminous  limestone  (Texas)  is  obtained 
"litho-carbon,"  used  in  varnish  making  and  so  largely  for  insu- 
lating purposes. 

Asphalt  is  a  subject  of  increasing  interest  and  value  to  civil 
and  municipal  engineers.  Its  use  in  construction  work  and  allied 
industries  is  advancing  in  a  most  rapid  manner  not  only  in 
amount  but  in  variety.  This  increase  in  municipal  use  is  com- 
paratively of  recent  date,  since  the  first  use  of  asphalt  for  street 
paving  in  this  country  was  in  Newark,  N.  J.,  in  1870. 

^  From  the  Rhone  Valley,  France,  between  the  towns  of  Bellegrade  and  Seyssel. 


EJNGINEERING   CHE)MISTRY  279 

AsPHAi^T  Pave:me:nt  Mixture). 

Asphalt  as  used  in  pavement  mixtures  is  usually  mixed  with  a 
more  liquid  bitumen  or  liquid  substitute,  to  reduce  its  brittleness 
and  to  increase  its  adhesiveness  to  the  mineral  portion  of  the 
pavement  mixture.  The  pavement  mixture  generally  consists 
of  asphaltic  cement,  9  to  13  per  cent.,  sand  83  to  70  per  cent.,  and 
pulverized  rock  5  to  15  per  cent.  The  proportions  of  these  in- 
gredients shall  be  determined  by  weight,  and  depend  upon  their 
kind  and  quality  and  the  traffic  upon  the  street.  The  mixture 
should  conform  to  the  following  requirements,  viz. :  It  shall  be 
homogeneous  and  tenacious,  free  from  brittleness  at  ordinary- 
temperatures,  and  not  be  too  soft  to  sustain  the  traffic  in  hot 
weather  nor  so  hard  as  to  be  brittle  in  cold  weather ;  it  must  not 
contain  less  than  9  per  cent,  of  total  bitumen  nor  more  than  12 
per  cent,  of  total  bitumen,  including  the  flux,  that  will  dissolve 
in  carbon  bisulphide.  The  flux  in  use  for  this  purpose  is  uni- 
formly a  heavy  residuum  prepared  by  the  removal  of  the  lighter 
portions  of  petroleum  by  distillation.  These  residues  naturally 
vary  in  character  in  the  same  way  that  the  petroleums  do  from 
which  they  have  been  derived.  The  oils  from  which  residuums 
or  fluxes  are  prepared  for  use  in  the  United  States  are  the 
paraffine  petroleums  from  the  Eastern  Ohio,  Kentucky,  Kansas, 
Oklahoma  and  Colorado  fields,  the  asphaltic  petroleum,  from 
California,  and  the  petroleum  of  mixed  character  from  Texas, 
containing  both  paraffine  and  asphaltic  hydrocarbons. 
Typicai.  PARArriNE  Fi.ux  of  1907. 
Manufacturer,  Solar  Refining  Co.,  Lima,  O. 

Specific  gravity 0-943 

Flash  point 455°  F- 

Volatile  7  hours  at  212°  F o.i  per  cent. 

"         "     "       "    235°  F.  (dry  sample) 0.2         *' 

Residue  at  78°  F crystalline,  slow  flow- 
Bitumen  insol.  88°  naphtha,  pitch 2.7  per  cent. 

Per  cent.  sol.  bit.  residues  by  H2SO4 24.9         " 

Paraffine  scale 6.4         " 

Fixed  carbon 2.8         " 


280  ENGINEERING   CHEMISTRY 

CaI^IEORNIA  ASPHAI.TIC  PETROLEUM  RESIDUUM. 

The  petroleums  of  California  are  characterized  by  the  fact 
that  the  residue  left  on  distillation,  if  the  latter  is  carried  suf- 
ficiently far,  is  a  solid  bitumen  resembling  asphalt.  The  oil  is 
said,  on  this  account,  to  have  an  asphaltic  base.  If  the  distilla- 
tion is  suspended  at  a  point  where  the  residue  does  not  solidify 
on  cooling  but  remains  liquid,  like  a  heavy  and  dense  natural 
maltha,  the  material  known  as  California  flux  is  obtained  which 
has  been  in  use  in  the  paving  industry  to  a  very  considerable 
extent  on  the  Pacific  Coast. 

Properties  : 
Trade  Name,  No.  2. 

Specific  gravity  dried  at  212°  F.    1.002 

Flash  test  (N.  Y.  State  oil  tester) 254°  F. 

r  Dry  substances — 

J  Loss  at  325°  F.   ( 7  hours) 5.0  per  cent. 

325    F.       1  Character  of  residue smooth 

(^  Penetration  of  residue  at  78°  F. soft 

Loss  400°  F.,  7  hours  ( fresh  sample) 16.7  per  cent. 


o  _>       -,  Character  of  residue smooth 

400    F.      I 

I  Penetration  of  residue  at  78°  F. soft 

Bitumen  soluble  in  CS2,  air  temperature 99.9  per  cent. 

Difference o.  i         " 

Mineral  matter 0.0         " 

1 00.0 
Bitumen  insoluble  in  88°  naphtha,  air  temp.,  pitch • .     7.6  per  cent. 

Per  cent,  of  soluble  bitumen  removed  by  H2SO4 48.3         •• 

Per  cent,  of  total  bittimen  as  saturated  hydrocarbons  47.9 

Per  cent,  of  solid  paraffines 0.0 

Fixed  carbon 6.0 

Methods  for  the  Examination  of  Bituminous  Road  Materials.^ 

CivASSlFlCATlON   OF   BITUMINOUS   ROAD   MaTE^RIAI^S. 

For  the  purpose  of  examination  bituminous  road  materials 
may  be  classified  under  the  following  headings : 

1.  Petroleums  and  petroleum  products,  including  residual 
petroleums,  fluxes,  oil-asphalts,  and  fluxed  or  cut-back  oil- 
asphalts. 

2.  Malthas. 

^  Bulletin  No.  38,  U.   S.  Dept.  Agriculture. 


DNGINEE^RING   CHEMISTRY  281 

3.  Asphalts  and  other  solid  native  bitumens,  and  asphaltic  ce- 
ments produced  by  fluxing  them. 

4.  Tar  and  tar  products. 

5.  Mixtures  of  tar  with  petroleum  or  asphalt  products,  bitum- 
inous emulsions,  and  factitious  asphalts. 

6.  Bituminous  aggregates,  including  rock  asphalts  or  bitum- 
inous rocks,  bituminous  concrete  and  asphalt  or  other  bituminous 
topping. 

Sche^me:  of  Examination. 
All  petroleum,  maltha,  and  solid  native  bitumen  products  are 
subjected  to  the  following  tests: 
Specific  gravity. 
Volatilization  at  163°  C. 
Bitumen  soluble  in  carbon  disulphide. 
Bitumen  insoluble  in  86°  B.  paraffine  naphtha. 
Fixed  carbon. 

Th^  SoHM^R  HyDRGMEJTER  for  ASPHAI.TS. 

This  is  graduated  from  0.85  to  1.3  at  25°  C,  as  recommended 
by  the  committee  of  the  American  Society  of  Civil  Engineers. 

The  principal  feature  of  the  method  is  to  allow  the  asphalt  to 
chill  in  a  small  cylindrical  vessel,  which  is  divided  into  two  parts, 
the  lower  part,  or  cup,  holding  exactly  10  cc,  and  the  upper  part, 
or  sleeve,  being  removable  from  the  cup  by  the  connecting  thread. 

The  entire  vessel  is  filled  with  melted  asphalt,  and  heated  for 
a  short  time  at  a  temperature  a  trifle  above  the  melting  point  in 
order  to  thoroughly  remove  air  bubbles  or  traces  of  water,  and 
after  the  surface  is  clear,  the  vessel  is  allowed  to  cool,  at  first  in 
air  temperature  (in  order  to  avoid  sudden  contraction  and  hence 
separation  of  the  asphalt  from  the  sides  of  the  tube)  and  then  in 
water  of  the  desired  temperature,  which  in  most  cases  will  be 
60°  F.  The  sample  should  be  left  in  water  a  suflicient  time 
(about  Yz  hour)  to  thoroughly  adopt  its  temperature,  and  after 
it  has  reached  it,  the  instrument  is  wiped  dry  and  the  upper 
extension  part  or  ''sleeve"  taken  off.  If  the  asphalt  is  so  hard 
that  it  renders  the  unscrewing  difficult,  the  upper  part  should  be 
warmed  with  a  Bunsen  burner. 


282 


ENGINEERING   CHEMISTRY 


When  the  "sleeve"  has  been  removed  the  asphalt,  which  extends 
above  the  level  of  the  lower  tube  or  cup,  is  cut  off  with  a  broad 
knife. 

The  cup  will  then  contain  exactly  lo  cc.  of  asphalt  at  60°  F. 
The  quantity  can  be  directly  weighed  out  on  an  analytical  bal- 


v^^V  II 


Fig.   48. — Sohmer   Hydrometer. 

ance,  and  the  specific  gravity  ascertained  by  dividing  the  number 
of  grams  of  asphalt  by  10.  The  following  method,  however, 
simplifies  the  procedure : 

The  cup  (A)  is  filled  flush,  as  described  above;  then  the 
cover  (B)  is  slid  on  it  from  the  side,  and  fastened  by  a  flange 
(C).     The  cup  and  its  contents  are  then  suspended   from  the 


Engine:ering  chi;mistry  283 

hydrometer  (Fig.  48),  and  the  whole  instrument  is  placed  in  a  jar 
containing  water  of  60°  F.  If  any  air  bubbles  should  form  on 
the  instrument,  it  should  be  quickly  twisted  once  or  twice  to 
allow  these  bubbles  to  escape.  The  specific  gravity  can  then  be 
read  directly  on  the  stem  of  the  hydrometer  without  correction. 
The  method  can  be  applied  for  asphalt,  road  oils,  tars,  wax, 
etc.;  the  instrument  having  a  range  of  0.850  to  1.700  specific 
gravity. 

Volatilization  Test. 

Equipment. 
I  constant-temperature  hot-air  oven  with  rubber  tubing.     (Fig.  49.) 

1  thermo-regulator. 

2  chemical  thermometers  reading  from  — 10°   C.  to  250°   C. 
I  tin  box,  6  centimeters  in  diameter  by  2  centimeters  deep. 

I  analytical  balance,  capacity  100  grams,  sensitive  to  o.i  milligram. 

Mejthod. 

The  object  of  the  volatilization  test  is  to  determine  the  per- 
centage of  loss  which  the  material  undergoes  when  20  grams  in 
a  standard-sized  container  are  subjected  to  a  uniform  tempera- 
ture of  163°  C.  for  5  hours,  and  also  to  ascertain  any  changes  in 
the  character  of  the  material  due  to  such  heating. 

The  oven  shown  in  Fig.  49,  known  as  the  New  York  Testing 
Laboratory  oven,  is  used  by  the  Office  of  Public  Roads,  although 
any  other  form  may  be  used  that  will  give  a  uniform  tempera- 
ture throughout  all  parts  where  samples  are  placed.  The  bulb 
of  one  of  the  thermometers  is  immersed  in  a  sample  of  some 
fluid,  non-volatile  bitumen,  while  the  other  is  kept  in  air  at  the 
same  level.  The  first  thermometer  serves  to  show  the  tempera- 
ture of  the  samples  during  the  test,  while  the  latter  gives  prompt 
warning  of  any  sudden  changes  in  temperature  due  to  irregulari- 
ties in  the  gas  pressure,  etc. 

Before  making  the  test  the  interior  of  the  oven  should  show  a 
temperature  of  163°  C.  as  registered  by  the  thermometer  in  air. 
The  tin  box  is  accurately  weighed  after  carefully  wiping  with  a 
towel  to  remove  any  grease  or  dirt.  About  20  grams  of  the 
material  to  be  tested  is  then  placed  in  the  box.     The  material 


284 


ENGINEEJRING   CHE:mISTRY 


may  then  be  weighed  on  a  rough  balance,  if  one  is  at  hand,  after 
which  the  accurate  weight,  which  should  not  vary  more  than 
0.2  gram  from  the  specified  amount,  is  obtained.  It  may  be 
necessary  to  warm  some  of  the  material  in  order  to  handle  it 
conveniently,  after  which  it  must  be  allowed  to  cool  before  deter- 
mining the  accurate  weight. 


Fig.  49. — New  York  Testing  L,aboratory  Oven. 

The  sample  should  now  be  placed  in  the  oven,  where  it  is 
allowed  to  remain  for  a  period  of  5  hours,  during  which  time  the 
temperature  as  shown  by  the  thermometer  in  bitumen  should  not 
vary  at  any  time  more  than  2°  C.  from  163°  C.  The  sample 
is  then  removed  from  the  oven,  allowed  to  cool,  and  reweighed. 
From  the  difference  between  this  weight  and  the  total  weight 
before  heating,  the  percentage  of  loss  on  the  amount  of  material 
taken  is  calculated. 

The  general  appearance  of  the  residue  should  be  noted,  espe- 
cially with  regard  to  any  changes  which  the  material  may  have 


ENGINEEiRING   CHJjMISTRY  285 

undergone.  Some  relative  idea  of  the  amount  of  hardening  which 
has  taken  place  may  be  obtained  from  the  results  of  a  float  or 
penetration  test  made  on  the  residue,  as  compared  with  the  results 
of  the  same  test  on  the  original  sample.  It  is  also  frequently 
desirable  to  make  the  specific  gravity  and  other  tests  on  the  resi- 
due for  the  purpose  of  identifying  or  ascertaining  the  character 
of  the  base  used  in  the  preparation  of  cut-back  products.  Before 
any  tests  are  made  on  the  residue,  it  should  be  melted  and  thor- 
oughly stirred  while  cooling. 

Use;  of  the;  VoIvATilization  Te;st. 

The  volatilization  test,  as  above  described,  is  made  on  prac- 
tically all  bitumens  with  the  exception  of  tars,  for  which  the  dis- 
tillation test  answers  a  similar  purpose.  The  test  is  also  fre- 
quently made  at  105°  C.  for  5  hours,  and  with  products  contain- 
ing small  amounts  of  water  it  is  usually  necessary  to  make  a  test 
at  the  lower  temperature  before  the  material  can  be  heated  at 
163°  C.  without  foaming  over.  In  the  case  of  emulsions  it  is 
customary  to  determine  the  loss  on  a  20-gram  sample  at  room 
temperature  for  24  hours,  after  which  the  sample  is  heated  at 
105°  C.  for  5  hours.  This  additional  loss  is  obtained  and  all 
determinations  are  made  on  the  dried  residue  and  reported 
accordingly. 

The  volatilization  test  is  also  occasionally  made  at  205°  C.  for 
5  hours  on  a  fresh  sample  in  order  to  show  the  effect  of  this 
higher  temperature  as  compared  with  the  results  at  163°  C. 

Determination  of  Bitumen  Soluble  in  Carbon  Bisulphide. 

Equipment. 
I  100  cc.  Erlenmeyer  flask. 

I  500  cc.  flask  with  side  neck  for  filtering  under  pressure. 
I  rubber  stopper  with  one  hole. 
I  filter  tube,  3.9  centimeters,  inside  diameter. 
I  platinum  gooch  crucible. 

1  piece  of   seamless   rubber  tubing,   about  3  centimeters   in  diameter 

and  3  centimeters  long. 
50  grams  of  long  fiber  amphibole  asbestos. 

2  wash  bottles ;  i  for  solvent,  i  for  water. 
I  Bunsen  burner. 


286 


e;ngine:e:ring  chemistry 


I  platinum  triangle. 

I  iron  tripod. 

I  drying  oven. 

I  desiccator  with  calcium  chloride. 

I  thermometer  reading  from  — io°  C.  to  iio°  C. 

I  vacuum  pump  and  connections. 

I  analytical  balance,  capacity  lOO  grams,  sensitive  to  o.i  milligram. 

Method. 

This  test  consists  in  dissolving  the  bitumen  in  carbon  disulphide 
and  recovering  any  insoluble  matter  by  filtering  the  solution 
through  an  asbestos  felt.  The  form  of  gooch  crucible  best 
adapted  for  the  determination  is  4.4  centimeters  wide  at  the  top, 
tapering  to  3.6  centimeters  at  the  bottom,  and  is  2.5  centimeters 
deep. 

For  preparing  the  felt  the  necessary  apparatus  is  arranged  as 
shown  in  Fig.  50,  in  which  a  is  the  filtering  flask,  b  a  rubber 


«f-- 


d— 


Fig.  so. — Apparatus  for  determining  soluble  bitumen. 

stopper,  c  the  filter  tube,  and  d  a  section  of  rubber  tubing  which 
tightly  clasps  the  gooch  crucible  e.  The  asbestos  is  cut  with 
scissors  into  pieces  not  exceeding  i  centimeter  in  length,  after 
which  it  is  shaken  up  with  just  sufficient  water  to  pour  easily. 
The   crucible   is   filled   with   the   suspended   asbestos,    which   is 


Engine;e;ring  chemistry  287 

allowed  to  settle  for  a  few  moments.  A  light  suction  is  then 
applied  to  draw  off  all  the  water  and  leave  a  firm  mat  of  asbestos 
in  the  crucible.  More  of  the  suspended  material  is  added,  and 
the  operation  is  repeated  until  the  felt  is  so  dense  that  it  scarcely 
transmits  light  when  held  so  that  the  bottom  of  the  crucible  is 
between  the  eye  and  the  source  of  light.  The  felt  should  then  be 
washed  several  times  with  water,  and  drawn  firmly  against  the 
bottom  of  the  crucible  by  an  increased  suction.  The  crucible  is 
removed  to  a  drying  oven  for  a  few  minutes,  after  which  it  is 
ignited  at  red  heat  over  a  Bunsen  burner,  cooled  in  a  desiccator 
and  weighed. 

From  2  to  3  grams  of  bitumen  or  about  10  grams  of  an  asphalt 
topping  or  rock  asphalt  is  now  placed  in  the  Erlenmeyer  flask, 
which  has  been  weighed  previously,  and  the  accurate  weight  of 
the  sample  is  obtained.  One  hundred  cubic  centimeters  of  chem- 
ically pure  carbon  disulphide  is  poured  into  the  flask  in  small 
portions,  with  continual  agitation,  until  all  lumps  disappear  and 
nothing  adheres  to  the  bottom.  The  flask  is  then  corked  and  set 
aside  for  15  minutes. 

After  being  weighed,  the  gooch  crucible  containing  the  felt  is 
set  up  over  the  dry  pressure  flask,  as  shown  in  Fig.  50,  and  the 
solution  of  bitumen  in  carbon  disulphide  is  decanted  through  the 
felt  without  suction  by  gradually  tilting  the  flask,  with  care  not 
to  stir  up  any  precipitate  that  may  have  settled  out.  At  the  first 
sign  of  any  sediment  coming  out,  the  decantation  is  stopped  and 
the  filter  allowed  to  drain.  A  small  amount  of  carbon  disulphide 
is  then  washed  down  the  sides  of  the  flask,  after  which  the  pre- 
cipitate is  brought  upon  the  felt  and  the  flask  scrubbed,  if  neces- 
sary, with  a  feather  or  ''policeman,"  to  remove  all  adhering 
material.  The  contents  of  the  crucible  are  washed  with  carbon 
disulphide,  until  the  washings  run  colorless.  Suction  is  then 
applied  until  there  is  practically  no  odor  of  carbon  disulphide  in 
the  crucible,  after  which  the  outside  of  the  crucible  is  cleaned 
with  a  small  amount  of  the  solvent.  The  crucible  and  contents 
are  dried  in  the  hot  air  oven  at  100°  S.  for  about  20  minutes, 
cooled  in  a  desiccator,  and  weighed.     If  any  appreciable  amount 


288  ENGINEERING   CHEMISTRY 

of  insoluble  matter  adheres  to  the  flask,  it  should  also  be  dried 
and  weighed,  and  any  increase  over  the  original  weight  of  the 
flask  should  be  added  to  the  weight  of  insoluble  matter  in  the 
crucible.  The  total  weight  of  insoluble  material  may  include  both 
organic  and  mineral  matter.  The  former,  if  present,  is  burned 
off  by  ignition  at  a  red  heat  until  no  incandescent  particles  remain, 
thus  leaving  the  mineral  matter  or  ash,  which  can  be  weighed  on 
cooling.  .  The  difference  between  the  total  weight  of  material 
insoluble  in  carbon  disulphide  and  the  weight  of  substance  taken 
equals  the  total  bitumen,  and  the  percentage  weights  are  calcu- 
lated and  reported  as  total  bitumen,  and  organic  and  inorganic 
matter  insoluble,  on  the  basis  of  the  weight  of  material  taken  for 
analysis. 

This  method  is  quite  satisfactory  for  straight  oil  and  tar  prod- 
ucts, but  where  natural  asphalts  are  present  it  will  be  found 
practically  impossible  to  retain  all  of  the  finely  divided  mineral 
matter  on  an  asbestos  felt.  It  is,  therefore,  generally  more  accu- 
rate to  obtain  the  result  for  total  mineral  matter  by  direct  igni- 
tion of  a  I -gram  sample  in  a  platinum  crucible  or  to  use  the 
result  for  ash  obtained  in  the  fixed  carbon  test.  The  total  bitu- 
men, is  then  determined  by  deducting  from  lOO  per  cent,  the  sum 
of  the  percentages  of  total  mineral  matter  and  organic  matter 
insoluble.  If  the  presence  of  a  carbonate  mineral  is  suspected, 
the  percentage  of  mineral  matter  may  be  most  accurately  obtained 
by  treating  the  ash  from  the  fixed  carbon  determination  with  a 
few  drops  of  ammonium  carbonate  solution,  drying  at  ioo°  C, 
then  heating  for  a  few  minutes  at  a  dull  red  heat,  cooling,  and 
weighing  again. 

When  difliculty  in  filtering  is  experienced — for  instance,  when 
Trinidad  asphalt  is  present  in  any  amount — a  period  of  longer 
subsidence  than  15  minutes  is  necessary,  and  the  following  method 
proposed  by  the  committee  on  standard  tests  for  road  materials 
of  the  American  Society  for  Testing  Materials  is  recommended : 

From  2  to  15  grams  (depending  on  the  richness  in  bitumen  of  the 
substance)  is  weighed  into  a  150  cc.  Erlenmeyer  flask,  the  tare  of  which 
has  been  previously  ascertained,  and  treated  with  100  cc.  of  carbon  disul- 
phide.    The  flask  is  then  loosely  corked  and  shaken  from  time  to  time 


ENGINKERING   CHEJMISTRY  289 

until  practically  all  large  particles  of  the  material  have  been  broken  up, 
when  it  is  set  aside  and  not  disturbed  for  48  hours.  The  solution  is  then 
decanted  off  into  a  similar  flask  that  has  been  previously  weighed,  as 
much  of  the  solvent  being  poured  off  as  possible  without  disturbing  the 
residue.  The  first  flask  is  again  treated  with  fresh  carbon  disulphide  and 
shaken  as  before,  when  it  is  put  away  with  the  second  flask  and  not  dis- 
turbed for  48  hours. 

At  the  end  of  this  time  the  contents  of  the  two  flasks  are  carefully 
decanted  off  upon  a  weighed  gooch  crucible  fitted  with  an  asbestos  filter, 
the  contents  of  the  second  flask  being  passed  through  the  filter  first.  The 
asbestos  filter  shall  be  made  of  ignited  long-fiber  amphibole,  packed  in 
the  bottom  of  a  gooch  crucible  to  the  depth  of  not  over  %  inch.  After 
passing  the  contents  of  both  flasks  through  the  filter,  the  two  residues 
are  shaken  with  more  fresh  carbon  disulphide  and  set  aside  for  24  hours 
without  disturbing,  or  until  it  is  seen  that  a  good  subsidation  has  taken 
place,  when  the  solvent  is  again  decanted  oft"  upon  the  filter.  This  wash- 
ing is  continued  until  the  filtrate  or  washings  are  practically  colorless. 

The  crucible  and  both  flasks  are  then  dried  at  125°  C.  and  weighed. 
The  filtrate  containing  the  bitumen  is  evaporated,  the  bituminous  residue 
burned,  and  the  weight  of  the  ash  thus  obtained  added  to  that  of  the 
residue  in  the  two  flasks  and  the  crucible.  The  sum  of  these  weights 
deducted  from  the  weight  of  substance  taken  gives  the  weight  of  bitumen 
extracted. 

Use  of  Totai,  Bitumen  Determination. 

This  determination  is  made  on  all  classes  of  bituminous  prod- 
ucts. In  the  analysis  of  tars  the  organic  matter  insoluble  is 
commonly  know^n  and  reported  as  "free  carbon." 

Determination  of  Bitumen  Insoluble  in  Paraffine  Naphtha. 

Equipment. 
The  apparatus  is  the  same  as  for  bitumen  soluble  in  carbon  disulphide. 

Method. 
This  determination  is  made  in  the  same  general  manner  as  the 
total  bitumen  determination  except  that  lOO  cc.  of  86°  B.  parafhne 
naphtha  is  employed  as  a  solvent  instead  of  carbon  disulphide. 
Considerable  difficulty  is  sometimes  experienced  in  breaking  up 
some  of  the  heavy  semi-solid  bitumens;  the  surface  of  the  ma- 
terial is  attacked,  but  it  is  necessary  to  remove  some  of  the  in- 

^  Proc.  Am.   Soc.  for  Testing  Materials,    1909,  Vol.  IX,  p.  221. 
19 


290  ENGINEERING   CHEMISTRY 

soluble  matter  in  order  to  expose  fresh  material  to  the  action  of 
the  solvent.  It  is,  therefore,  advisable  to  heat  the  sample  after  it 
is  weighed,  allowing  it  to  cool  in  a  thin  layer  around  the  lower 
part  of  the  flask.  If  difficulty  is  still  experienced  in  dissolving  the 
material,  a  rounded  glass  rod  will  be  found  convenient  for  break- 
ing up  the  undissolved  particles.  Not  more  than  one-half  of  the 
total  amount  of  naphtha  required  should  be  used  until  the  sample 
is  entirely  broken  up.  The  balance  of  the  100  cc.  is  then  added, 
and  the  flask  is  twirled  a  moment  in  order  to  mix  the  contents 
thoroughly,  after  which  it  is  corked  and  set  aside  for  30  minutes. 

In  making  the  filtration  the  utmost  care  should  be  exercised  to 
avoid  stirring  up  any  of  the  precipitate,  in  order  that  the  filter 
may  not  be  clogged  and  that  the  first  decantation  may  be  as  com- 
plete as  possible.  The  sides  of  the  flask  should  then  be  quickly 
washed  down  with  naphtha  and,  when  the  crucible  has  drained, 
the  bulk  of  insoluble  matter  is  brought  upon  the  felt.  Suction 
may  be  applied  when  the  filtration  by  gravity  almost  ceases,  but 
should  be  used  sparingly,  as  it  tends  to  clog  the  filter  by  packing 
the  precipitate  too  tightly.  The  material  on  the  felt  should  never 
be  allowed  to  run  entirely  dry  until  the  washing  is  completed,  as 
shown  by  the  colorless  filtrate.  When  considerable  insoluble 
matter  adheres  to  the  flask,  no  attempt  should  be  made  to  remove 
it  completely.  In  such  cases  the  adhering  material  is  merely 
washed  until  free  from  soluble  matter,  and  the  flask  is  dried  with 
the  crucible  at  100°  C.  for  about  i  hour,  after  which  it  is  cooled 
and  weighed.  The  percentage  of  bitumen  insoluble  is  reported 
upon  the  basis  of  total  bitumen  taken  as  icx). 

The  difference  between  the  material  insoluble  in  carbon  disul- 
phide  and  in  the  naphtha  is  the  bitumen  insoluble  in  the  latter. 
Thus,  if  in  a  certain  instance  it  is  found  that  the  material  in- 
soluble in  carbon  disulphide  amounts  to  i  per  cent,  and  that  10.9 
per  cent,  is  insoluble  in  naphtha,  the  percentage  of  bitumen  in- 
soluble would  be  calculated  as  follows: 

Bitumen  insoluble  in  naphtha       10. 9 — i       9.9 

oA  ^  1  U-. — =  —  =  10  per  cent. 

Total  bitumen  100 — i        99 


i:ngine;e:ring  chemistry  291 

Us^  OF  Naphtha  Insolubi^k  Bitumejn  Determination. 

This  test  is  made  on  all  petroleums,  malthas,  asphalts,  and 
other  solid  native  bitumens  and  their  products. 

It  should  be  noted  that  petroleum  naphthas  are  by  no  means 
definite  compounds,  but  are  composed  of  a  number  of  hydro- 
carbons which  vary  in  character  and  quantity  according  to  the 
petroleum  from  which  they  have  been  distilled.  Their  solvent 
powers  also  vary  greatly.  Thus  naphthas  produced  from  as- 
phaltic  petroleums,  consisting  mainly  of  naphthene  and  poly- 
methylene  hydrocarbons,  are  much  more  powerful  solvents  of  the 
heavier  asphaltic  hydrocarbons  than  are  the  paraffine  naphthas. 
The  density  of  the  naphtha  also  affects  its  solvent  power,  for 
those  of  high  specific  gravity  dissolve  the  heavier  hydrocarbons 
more  readily  than  those  of  lower  specific  gravity.  As  the  main 
object  of  this  test  is  to  separate  the  heavier  hydrocarbons  of  an 
asphaltic  nature  from  the  paraffine  hydrocarbons,  a  paraffine  sol- 
vent should  be  employed,  and  for  ordinary  purposes  a  paraffine 
naphtha  of  86°  B.  gravity,  distilling  between  40°  C.  and  65°  C, 
has  been  found  to  be  readily  obtainable  and  fairly  satisfactory. 
The  solvent  action  of  88°  B.  naphtha  is  a  little  lower,  and  there- 
fore preferable,  but  it  can  not  be  as  readily  obtained. 

The  determination  is  also  frequently  made  with  heavier  naph- 
thas, such  as  66°  B.  and  y2'^  B.,  for  the  purpose  of  grading  the 
character  of  the  bitumen  present  in  the  compound.  A  report 
should  therefore  always  distinctly  state  the  gravity  and  character 
of  the  solvent  used. 

Determination  of  Bitumen  Insoluble  in  Carbon  Tetrachloride. 

Equipment. 
The  apparatus  is  the  same  as  for  bitumen  soluble  in  carbon  disulphide. 

Method. 

This  determination  is  conducted  in  exactly  the  same  manner 
as  described  under  "Determination  of  bitumen  soluble  in  carbon 
disulphide,"  using  100  cc.  of  chemically  pure  carbon  tetrachloride 
in  place  of  carbon  disulphide. 

The  percentage  of  bitumen  insoluble  is  reported  upon  the  basis 


292  ENGINEERING   CHEMISTRY 

of  total  bitumen  taken  as  100,  as  described  under  "Determination 
of  bitumen  insoluble  in  paraffine  naphtha." 

Use  of  Determination  of  Bitumen  Insoeubee  in  Carbon 
Tetracheoride. 

The  bitumen  insoluble  in  carbon  tetrachloride,  but  soluble  in 
carbon  disulphide,  is  commonly  known  as  "carbenes."  The  test 
is  occasionally  made  on  petroleums,  asphalts,  and  other  solid 
native  bitumens  and  their  products,  for  the  purpose  of  identifi- 
cation, or  when  there  is  any  reason  to  suspect  that  the  material 
under  examination  has  been  injured  by  overheating  during  the 
process  of  manufacture. 

Determination  of  Fixed  Carbon. 

Equipment. 
I  iron  ring  support  (ring  7.5  centimeters  in  diameter). 
I  platinum  triangle. 
I  Bunsen  burner  and  rubber  tubing. 
I  platinum  crucible  with  a  tight-fitting  cover   (weight  complete,  from 

20  to  30  grams). 
I  crucible  tongs. 

I  desiccator  with  calcium  chloride. 
I  analytical  balance,  capacity  100  grams,  sensitive  to  o.i  milligram. 

Method. 
This  determination  is  made  in  accordance  with  the  method  de- 
scribed for  coal  in  the  Journal  of  the  American  Chemical  vSociety, 
1899,  volume  21,  page  11 16.  One  gram  of  the  material  is  placed 
in  a  platinum  crucible  weighing  from  20  to  30  grams  and  having 
a  tightly  fitting  cover.  It  is  then  heated  for  7  minutes  over  the 
full  flame  of  a  Bunsen  burner,  as  shown  in  Fig.  15.  The  crucible 
should  be  supported  on  a  platinum  triangle  with  the  bottom  frohi 
6  to  8  centimeters  above  the  top  of  the  burner.  The  flame  should 
be  fully  20  centimeters  high  when  burning  freely,  and  the  determ- 
ination should  be  made  in  a  place  free  from  drafts.  The  upper 
surface  of  the  cover  should  burn  clear,  but  the  under  surface 
should  remain  covered  with  carbon,  excepting  in  the  case  of  some 
of  the  more  fluid  bitumens,  when  the  under  surface  of  the  cover 
may  be  quite  clean. 


ENGINEE^RING   CHEJMISTRY  293 

The  crucible  is  removed  to  a  desiccator  and  when  cool  is 
weighed,  after  which  the  cover  is  removed,  and  the  crucible  is 
placed  in  an  inclined  position  over  the  Bunsen  burner  and  ignited 
until  nothing  but  ash  remains.  Any  carbon  deposited  on  the 
cover  is  also  burned  off.  The  weight  of  ash  remaining  is  deducted 
from  the  weight  of  the  residue  after  the  first  ignition  of  the 
sample.  This  gives  the  weight  of  the  so-called  fixed  or  residual 
carbon,  which  is  calculated  on  a  basis  of  the  total  weight  of  the 
sample,  exclusive  of  mineral  matter.  If  the  presence  of  a  car- 
bonate mineral  is  suspected,  the  percentage  of  mineral  matter 
may  be  most  accurately  obtained  by  treating  the  ash  with  a  few 
drops  of  ammonium  carbonate  solution,  drying  at  ioo°  C,  then 
heating  for  a  few  minutes  at  a  dull  red  heat,  cooling  and  weighing. 
Use  of  Determination  for  Fixed  Carbon. 

This  determination  is  made  on  all  bituminous  products  with  the 
exception  of  tars,  upon  which  reliable  results  cannot  be  obtained, 
owing  to  the  error  introduced  by  the  presence  of  considerable 
quantities  of  free  carbon. 

Determination  of  Paraffine  Scale. 

Eqijipment. 
I  200  cc.   (6-ounce)   glass  retort   (for  each  determination). 
I  150  cc.  Erlenmeyer  flask, 
I  100  cc.  Erlenmeyer  flask. 

I  500  cc.  (i6-ounce)  flask,  with  side  neck  for  filtering  under  pressure. 
I  glass  funnel  65  millimeters  in  diameter,  stem  150  millimeters  long. 

1  freezing  mixture  reservoir. 

2  rubber  stoppers  with  hole. 

I  analytical  balance,  capacity  100  grams,  sensitive  to  o.i  milligram. 

I  rough  balance,  capacity  i  kilogram,  sensitive  to  o.i   gram. 

I  wash  bottle. 

I  quart  tin  cup,  seamless. 

I  package  C.  S.  &  S.  9-centimeter  hardened  filter  papers. 

I  vacuum  pump  and  connections. 

I  glass  crystallizing  dish  50  millimeters  in  diameter. 

I  steam  bath. 

I  desiccator  with  calcium  chloride. 

I  4-inch  steel  spatula. 

I  Bunsen  burner  with  rubber  tubing. 

I  iron  stand  with  retort  clamp. 


294 


ENGINEERING   CHEMISTRY 


Method. 

One  hundred  grams  of  the  material  under  examination  should 
be  weighed  into  the  tared  glass  retort  and  distilled  as  rapidly  as 
possible  to  dry  coke.  The  distillate  is  caught  in  a  150  cc.  Erlen- 
meyer  flask,  the  weight  of  which  has  been  previously  ascertained. 
During  the  early  stages  of  distillation  a  cold,  damp  towel  wrapped 
around  the  stem  of  the  retort  will  serve  to  condense  the  distillate. 
After  high  temperatures  have  been  reached,  this  towel  may  be 
removed.  When  the  distillation  is  completed,  the  distillate  is  al- 
lowed to  cool  to  room  temperature  and  is  then  weighed  in  the 
flask.  This  weight  minus  that  of  the  flask  gives  the  weight  of 
the  total  distillate. 


Fig.  51. — Apparatus  for  determining  paraffine  scale. 


Five  grams  of  the  well  mixed  distillate  is  then  weighed  into  a 
100  cc.  Erlenmeyer  flask  and  mixed  with  25  cc.  of  Squibb's  ether. 
Twenty-five  cubic  centimeters  of  Squibb's  absolute  alcohol  is  then 
added,  after  which  the  flask  is  packed  closely  in  a  freezing  mix- 
ture of  finely  crushed  ice  and  salt  maintained  at  — 18°  C.  in  a 
quart  tin  cup.  After  remaining  30  minutes  in  this  mixture,  the 
solution  is  quickly  filtered  through  a  No.  575  C.  S.  &  S.  9  centi- 


ENGINEERING   CHEMISTRY  295 

meter  hardened  filter  paper  placed  in  a  glass  funnel,  which  is 
packed  in  a  freezing  mixture,  as  shown  in  Fig.  51.  Vacuum 
should  be  employed  to  hasten  filtration.  The  freezing-mixture 
reservoir  (b)  shown  in  Fig.  51  may  be  made  by  cutting  in  half  a 
round  glass  bottle  measuring  approximately  120  millimeters  in 
diameter  and  using  the  upper  half  in  an  inverted  position.  Any 
precipitate  remaining  on  the  paper  should  be  washed  until  free 
from  oil  with  about  50  cc.  of  a  i  to  i  mixture  of  Squibb's  ether 
and  absolute  alcohol  cooled  to  — 18°  C. 

After  the  paper  has  been  sucked  dry,  it  should  be  removed  from 
the  funnel  and  the  adhering  paraffine  scale  should  be  scraped  off 
into  a  weighed  crystallizing  dish  and  dried  on  a  steam  bath.  The 
dish  and  contents  should  then  be  cooled  in  a  desiccator  and 
weighed. 

The  weight  of  the  parafiine  scale  so  obtained,  divided  by  the 
weight  of  the  distillate  taken  and  multiplied  by  the  percentage 
of  the  total  distillate  obtained  from  the  original  sample,  equals 
the  percentage  of  the  parafiine  scale. 

Use  01^  Paraeeine  ScaeE  Determination. 

The  parafiine  scale  determination  may  be  made  on  all  native 
bitumens  and  their  products  which  are  suspected  of  being  of  a 
parafiine  nature.  It  is  not  an  extremely  accurate  determination, 
however,  and  is  seldom  employed  by  the  Ofiice  of  Public  Roads. 

Penetration  Test. 

The  object  of  the  penetration  test  is  to  ascertain  the  consistency 
of  the  material  under  examination  by  determining  the  distance  a 
weighted  needle  will  penetrate  into  it  at  a  given  temperature. 

There  are  two  machines  in  use  for  this  purpose :  The  Dow  and 
the  New  York  Testing  Laboratory  penetrometer.  The  latter  is 
used  by  the  Ofiice  of  Public  Roads  and  is  thus  described  by  Mr. 
C.  N.  Forrest,  chief  chemist.  New  York  Testing  I^aboratory,  in 
a  communication  to  the  editor : 

The  consistency  of  asphalt  cement  or  of  a  similar  material  is 
determined  by  the  depth  to  which,  under  a  definite  load  and  dur- 
ing a  given  time  a  standard  needle  will  penetrate. 


296 


DNGINEKRING   CHEMISTRY 


An  instrument  especially  designed  for  this  purpose  is  shown 
in  the  accompanying  illustration,  Fig.  52. 

The  base  and  foot  casting  A  can  be  leveled  by  means  of  the 
thumb  screws  B,  and  is  bored  to  lit  the  standard  C  and  also  the 
platen  D,  which  by  means  of  screw  on  shank  of  platen  raises  or 


Fig.    52. — Penetrometer. 

lowers  the  revolving  disc  E,  on  which  is  to  be  placed  the  sample 
of  the  material  to  be  tested. 

The  standard  C  carries  a  bracket  F,  adjustable  as  to  elevation 
by  thumb  screws  R,  and  also  the  bracket  G,  which  on  back  carries 
the  clockwork  H,  timing  the  duration  of  the  test  by  half-second 


DNGINEEJRING   CHEMISTRY  297 

beats,  and  on  the  front  the  dial  J,  divided  into  360  degrees,  with 
the  hand  K  marking  the  number  of  degrees,  each  of  which  repre- 
sents Yio  miUimeter  of  penetration  measured  by  rack  on  sliding 
gauge  L,  engaging  in  pinion  on  shaft  which  actuates  the  hand 
K.  The  pointer  M  serves  as  a  marker  for  the  pendulum  P. 
The  beveled  edge  mirror  N,  adjustable  through  universal  joints, 
serves  to  reflect  light  on  the  sample  under  test.  O  is  a  plunger 
or  brake  which  holds  the  needle  bar,  representing  weight  of  50 
grams  and  superincumbent  weight  in  place  until  pressed  inward, 
which  movement  permits  needle  and  weight  to  act  upon  test 
block  without  friction,  and  is  easily  operated  by  grasping  the 
horns  Q  between  two  fingers  and  pressing  brake  head  O  with 
thumb.  S  is  a  weight  of  predetermined  capacity,  either  50  or  150 
grams. 

A  No.  2  R.  J.  Roberts  needle  has  been  selected  as  standard, 
and  this  is  set  in  a  short  brass  shaft  for  greater  convenience  in 
handling. 

Five  seconds  is  the  length  of  time  the  needle  should  be  per- 
mitted to  penetrate ;  yy^  F.  or  25°  C.  is  the  standard  temperature. 

One  hundred  grams  is  the  standard  weight,  which  includes  the 
weight  of  the  needle. 

In  order  to  test  the  stability  of  a  cement  at  a  higher  or  lower 
temperature  than  jy^  F.  a  lighter  or  heavier  load  may  be  re- 
quired, and  for  this  purpose  the  penetrometer  is  supplied  with 
adjustable  weights  which  permit  of  the  use  of  a  50,  100  or  200 
gram  load  upon  the  needle  as  desired. 

At  32°  F.  a  200-gram  load,  while  at  100°  or  115°  F.  but  50 
grams  may  be  required,  in  order  to  permit  a  measurement  within 
the  compass  of  the  scale  on  the  dial. 

It  is  necessary  that  the  substance  to  be  tested  should  be  of  a 
uniform  and  standard  temperature.  Bituminous  substances  should 
present  a  fresh  surface  which  has  been  melted  not  longer  than  a 
day  before  making  the  test,  as  exposure  to  the  air  and  a  deposit 
of  dust  soon  harden  the  exterior  sufficiently  to  affect  the  penetra- 
tion. 

It  is  usually  sufficient  to  immerse  the  sample  of  bitumen  in 


298  e:ngine:e:ring  chkmistry 

water  maintained  at  yy^  F.  for  j/^  hour  in  order  to  bring  it 
to  a  uniform  temperature,  but  this  time  may  have  to  be  lengthened 
if  the  material  is  either  very  warm  or  cold  when  it  is  placed  in 
the  water.  If  a  small  room  is  available  in  which  the  temperature 
may  be  regulated  to  "j^j^  F.  it  will  facilitate  the  operation. 

The  substance  should  be  melted  and  poured  into  a  2-ounce  tin 
sample  box,  about  2^  inches  in  diameter  and  ^^  inch  deep,  cooled 
by  first  placing  in  ice  water  and  then  brought  to  the  proper  tem- 
perature for  testing  {j'j^  F.)  by  immersing  in  water  maintained 
at  this  temperature  for  about  ^  hour.  It  is  then  placed  upon 
the  revolving  table  E  of  the  penetrometer,  and  raised  until  the 
surface  of  the  sample  just  touches  the  point  of  the  needle.  The 
foot  of  the  rack  L  should  rest  upon  the  rod  carrying  the  weight 
and  the  needle.  The  position  of  the  hand  should  be  noted.  Re- 
lease the  rod  by  pressing  the  plunger  O  for  a  period  of  5  seconds, 
then  again  move  the  rack  ly  down,  until  the  foot  rests  upon 
the  rod,  and  the  difference  in  the  reading  on  the  dial  will  repre- 
sent the  depth  in  tenths  of  a  millimeter  which  the  needle  has 
penetrated  the  sample,  or  its  consistency  in  degrees  at  the  standard 
temperature. 

Float  Test  or  Fluidity  Test. 

The  consistency  or  fluidity  of  bituminous  binders  is  of  great 
importance,  both  as  a  first  consideration  to  insure  selection  of 
the  appropriate  type  and  during  use,  uniformity  and  perfect  con- 
trol of  the  work,  just  as  it  is  in  the  sheet  asphalt  paving  industry. 
It  is  obvious  that  a  binder  intended  for  use  as  a  surface  dressing 
should  be  of  quite  a  different  consistency  from  one  which  is  to 
be  incorporated  with  stone  to  form  the  wearing  body  of  the 
highway.    No  single  preparation  will  answer  all  requirements. 

It  has  been  proposed  that  a  temperature  of  90°  F.  be  consid- 
ered as  a  normal  standard  at  which  to  test  the  consistency  of 
road  binders  of  a  bituminous  nature,  because  that  is  a  fair  con- 
dition upon  a  road  during  suitable  working  weather,  and  a  com- 
pound should  be  capable  of  being  worked  to  some  extent,  at 
least,  at  this  temperature,  if  it  is  to  be  mixed  with  cool  stone  or 
swept  into  the  interstices  of  a  roadbed.     A  much  more  fluid  ma- 


Enginee:ring  chemistry 


299 


terial  is  required  for  such  use  than  in  the  older  forms  of  bitu- 
minous pavements,  the  mixture  for  which  is  taken  from  a  cen- 
tral plant  in  a  hot  condition  and  the  standard  forms  of  pene- 
trometers mentioned  above  are  not  available  for  regulating  the 
consistency  of  the  same. 


Tests  of  the  Consistency  of  Bituminous  Binders   for  Highways. 


Materials 


Refined  water  gas  tar.. 

Crude  coal-tar 

Tarvia 

Tarina 

Texas  flux  oil 

Cahf.  flux  oil 

Headley  oil,  No.  2 

Headley  oil,  No.  3.  •  -  • 
Headley  oil,  No.  4.  •  • . 

Genasco  compound 

Genasco  compound . .  •  • 

Genasco  compound 

Standard  Oil  Co 

Standard  Oil  Co 

Standard  Oil  Co 

Standard  Oil  Co 

Standard  Oil  Co 


N.  Y.  T.  I,. 

Viscosimeter 

at  90°  F. 

Min.      Sec. 


O 
O 
I 
O 
O 

3 
o 

2 

6 

ID 

'69 

II 
o 
o 
o 
o 
I 


20 

30 
30 
16 

51 
40 

35 
53 
56 
54 
55 
54 
6 
12 
23 
39 
24 


Engler  viscosimeter.        100  cc.  flow  at 


77°  F. 
Min.      Sec. 


Too   Stiff 

Too  Stiff 
Too  stiff 
17  10 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
5  38 

Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 


130°  F. 
Min.      Sec. 


9  46 

9  8 

Too  stiff 
3_         18 

Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
Too  stiff 
I  36 

3  o 

Too  stiff 
Too  stiff 
Too  stiff 


250°  F. 
Min.      Sec. 


50 

30 

2 


34 
32 
14 
6 
30 
42 

8  30 
Too  stiff 

9  28 
32 
38 
56 
18 
26 


1  N.  Y.  T.  I,aby.  test  at  i5o°F.  =  2  min.  18  sec. 

The  Engler  viscosimeter  is  in  general  use  for  testing  fluid  com- 
pounds, such  as  oils,  at  any  desired  temperature,  but  is  not  avail- 
able for  the  highly  cementitious  and  semi-fluid  asphaltic  materials 
now  preferred  by  road  engineers,  except  at  temperatures  above 
200°  F. 

To  provide  an  instrument  for  controlling  the  consistency  of 
semi-fluid  compounds  intended  for  road  building  the  author  has 
elaborated  a  simple  form  of  viscosimeter,  originally  suggested 
by  Mr.  E.  C.  Wallace,  now  with  the  Warren  Brothers  Company, 
which  fills  the  gap  for  substances  between  those  which  are  sufli- 
ciently  fluid  for  the  Engler  type  of  viscosimeter  and  the  semi- 
solid cements  heretofore  regulated  by  penetration  instruments. 


300 


e:ngine:e:ring  che;mistry 


The  apparatus  which  is  made  by  Howard  &  Morse,  Brooklyn, 
N.  Y.,  consists  of  two  parts,  an  aluminum  float  or  saucer  and  a 
conical  brass  collar.  The  two  parts  are  shown  in  the  drawing 
(Fig.  53)  and  are  made  separately  for  reasons  of  economy,  so 


f^^ 


h-  z  H 


Fig-   53- — Instrument  for  determining  the  consistency  of  road  binders. 

that  one  or  two  of  the  floats  will  be  sufficient  for  an  indefinite 
number  of  brass  collars. 

In  using  the  apparatus  the  brass  collar  is  placed  upon  a  brass 
plate,  the  surface  of  which  has  been  amalgamated,  and  filled  with 


ENGINEERING   CHEMISTRY  3OI 

the  bitumen  under  examination,  after  it  has  been  softened  suffi- 
ciently to  flow  freely  by  gentle  heating.  The  collar  must  be  level 
full,  and  as  soon  as  the  bitumen  has  cooled  sufficiently  to  handle 
it  is  placed  in  ice  water  at  41°  F.  for  15  minutes.  It  is  then  at- 
tached to  a  float  and  immediately  placed  upon  the  surface  of  the 
water,  which  is  maintained  at  90°  F.,  or  any  other  temperature 
desired. 

As  the  plug  of  bitumen  in  the  brass  collar  becomes  warm  and 
fluid,  it  is  gradually  forced  out  of  the  collar,  and  as  soon  as  the 
water  gains  entrance  to  the  saucer  the  entire  apparatus  sinks  be- 
low the  surface  of  the  same. 

The  time,  in  seconds,  elapsing  between  placing  the  apparatus 
on  the  water  and  when  it  sinks  is  determined  most  conveniently 
by  means  of  a  stop  watch,  and  is  considered  as  the  consistency  of 
the  bitumen  under  examination. 

This  device  has  been  in  general  use  in  the  New  York  Testing 
Laboratory  for  some  time.  An  equipment  of  12  brass  collars, 
2  aluminum  saucers,  a  nursery  refrigerator  for  ice  water,  and 
an  open  tank  holding  about  i  quart  of  water  and  heated  by  a 
Bunsen  burner  is  sufficient  for  testing  a  great  many  samples.  A 
thermostat  in  the  water  bath  will  assist  in  maintaining  a  constant 
temperature, 

From  the  data  presented  in  the  table  on  page  299  it  will  be 
observed  that  this  device  is  available  at  90°  F.  for  testing  almost 
any  compound  (bituminous)  used  in  road  building  except  light 
oils. 

The  Engler  viscosimeter  for  tests  at  250°  F.  to  350°  F.  and 
the  New  York  Testing  Laboratory  device  at  90°  F.  provide 
satisfactory  means  for  making  these  consistency  tests. 

Ductility  Test. 

This  test,  as  applied  to  asphalts,  asphaltic  cements,  or  bitumens, 
measures  the  distance  in  centimeters  through  which  a  briquette 
of  standard  size  can  be  pulled  at  a  given  speed  and  a  given  tem- 
perature before  rupture  takes  place.  Generally  speaking,  the 
more  ductile  the  material  the  greater  the  cementing  value.    Apart 


302  DNGINEE^RING   CHE^MISTRY 

from  the  nature  of  the  bitumen  itself,  the  more  important  condi- 
tions affecting  its  ductiUty  are : 

Purity. 

Consistency. 

Size  and  shape  of  briquette. 

Rapidity  of  pull. 

Temperature  at  which  test  is  made. 
Purity. — If  the  bituminous  material  contains  considerable  quan- 
tities of  inert  or  non-bituminous  matter,  it  will  ordinarily  show 
a  lower  ductility  than  it  would  if  these  matters  were  removed. 

Consistency. — With  the  same  kind  of  bitumen,  the  softer  the 
consistency  the  greater  will  be  the  ductility. 

The  machine  generally  used  for  determining  the  ductility^  of 
bitumens  is  the  "Smith  Horizontal  Ductility  Machine"  and  is 
thus  described : 

GenErai,  Description. 

This  machine  consists  of  a  horizontal  trough  L,  with  suitable 
mechanism  attached  for  pulling  apart  the  two  ends  of  a  briquette 
D  of  standard  size  until  rupture  takes  place.  Means  for  regu- 
lating the  speed  of  the  machine  and  for  measuring  the  distance 
between  the  two  clips  at  the  point  of  rupture  are  provided.  Two 
different  types  of  machine  are  made : 

A.  The  hand  power  machine. 

B.  The  motor  driven  machine. 

In  the  hand  driven  machine  the  revolution  of  a  hand  wheel  H 
operates  to  move  the  traveling  carriage.  The  speed  is  regulated 
by  means  of  a  clicking  device  K  attached  to  the  driving  mechan- 
ism. When  the  wheel  is  rotated  at  such  a  speed  that  the  clicks 
produced  by  the  clicking  device  synchronize  with  a  metronome 
set  to  beat  79  beats  per  minute,  the  traveling  carriage  of  the 
machine  will  be  moved  forward  at  the  standard  speed  for  mak- 
ing ductility  tests  at  yy°  F. ;  vi^.,  5  centimeters  per  minute. 

In  the  motor  driven  machine  the  gearing  is  so  arranged  that 
when  the  motor  is  given  the  full  current  under  which  it  is  de- 
signed to  operate  (  volts  amperes),  the  traveling  car- 
riage will  be  moved  forward  at  the  rate  of  5  centimeters  per 


KNGINEJERING    CHEJMISTRY 


303 


minute.    Where  special  speeds  are  desired,  suitable  interchange- 
able gears  will  be  provided,  thus  permitting  variations  in  speed. 

Operation  01^  Machine. 
In  operating  the  machine  the  box  L,  is  first  filled  with  water 
at  the  required  temperature  to  such  a  depth  that  the  briquettes 
while  they  are  being  pulled  will  be  completely  immersed  in  it. 
The  hand  wheel  H  of  the  machine  is  then  rotated  so  as  to 
bring  the  traveling  carriage  B  down  to  the  point  where  the  dis- 
tance between  the  pins  P  on  the  shelves  attached  to  the  travel- 
ing carriage  and  to  one  end  of  the  machine  will  be  approximatel)' 
the  same  as  the  distance  between  the  holes  in  the  ends  of  the 
briquette  molds  D  when  they  are  set  up  as  described  hereafter. 


Fig.   54. — Electrically  driven. 

The  briquette  is  then  placed  in  the  machine  by  slipping  the  rings 
or  holes  in  the  ends  of  the  mold  over  the  pins  previously  men- 
tioned. The  hand  wheel  is  then  rotated  in  such  a  manner  as  to 
draw  the  traveling  carriage  away  from  the  end  of  the  machine 
until  it  just  begins  to  exert  a  tension  upon  the  briquette.  The 
measuring  rule  E  attached  to  the  side  of  the  machine  is  then 
moved  in  the  loosely  fitting  clip  A  which  hold  it  until  the  zero 
mark  on  the  scale  is  exactly  opposite  the  pointer  M  on  the 
traveling  carriage  of  the  machine.    The  machine  is  then  operated 


304 


ENGINJ^ERING   CHEMISTRY 


^1 


pa 


CD 


DNGINDERING    CHEMISTRY  305 

at  the  required  speed  and  the  traveling  carriage  draws  apart  the 
two  ends  of  the  briquette. 

When  the  thread  produced  by  puUing  out  the  briquette  breaks, 
the  distance  through  which  the  briquette  has  been  pulled  will  be 
indicated  by  the  position  of  the  pointer  on  the  measuring  scale, 
which  is  divided  into  centimeters,  and  this  distance,  expressed 
in  centimeters,  is  reported  as  the  ductility  of  the  material  ex- 
amined. 

A  thermometer  reading  to  i°  F.  inserted  in  a  cork,  should  be 
placed  in  the  circular  hole  in  the  traveling  carriage  so  as  to  regis- 
ter the  temperature  of  the  water  during  the  test. 

During  the  operation  of  pulling,  the  temperature  of  the  water 
should  not  vary  more  than  ^°  from  the  standard  temperature. 

While  this  test  is  usually  conducted  at  yy^  F.,  it  may  also  be 
made  at  32°  F.  When  made  at  this  latter  temperature,  extreme 
care  must  be  taken  not  to  fracture  the  briquette,  as  materials  of 
this  kind  are  frequently  very  brittle  at  low  temperatures.  For 
this  reason  it  is  customary  to  pull  the  briquettes  apart  at  the  rate 
of  34  centimeter  per  minute  while  testing  at  32°  F.,  instead  of 
5  centimeters  per  minute  as  employed  when  testing  them  at  yy°  F. 

The  traveling  carriage  is  provided  with  a  slip  nut  attachment  in 
order  to  facilitate  bringing  it  back  to  its  original  position  after 
a  test  has  been  made.  By  throwing  back  the  clips  on  the  ends 
of  the  slip  nuts  and  opening  them  out,  the  carriages  can  be  moved 
by  hand  without  rotating  the  operating  wheel. 

Standard  Conditions  for  Making  Ductility  Test. 

Purity. — The  asphalt,  if  necessary,  must  be  purified  as  described 
elsewhere  herein  until  it  consists  substantially  of  pure  bitumen. 
Specifications  usually  define  the  ductility  required  for  the  pure 
bitumen.  Where  the  specification  calls  for  a  ductility  consider- 
ably lower  than  that  possessed  by  the  bitumens  under  examination, 
it  is  not  always  necessary  to  go  through  the  purifying  process.  If 
the  impure  bitumen  shows  a  ductility  in  excess  of  the  specification 
requirements  for  pure  bitumen,  it  is  certain  that  the  purified  bi- 
tumen would  comply  with  these  requirements. 

Where  the  impure  bitumen  shows  a  lower  ductility  than  called 


3o6  e;ngine:e:ring  chemistry 

for  by  the  specifications  for  pure  bitumen,  it  will  of  course  be 
necessary  to  purify  the  bitumen  under  examination. 

Consistency. — Specifications  usually  call  for  a  certain  ductility 
at  50  penetration  and  sometimes  provide  for  a  variation  from 
this  consistency  by  calling  for  a  higher  ductility  if  the  material 
is  softer  than  50  penetration  and  a  lower  ductility  if  the  material 
is  harder  than  50  penetration.  The  generally  allowed  ratio  of 
increase  or  decrease  is  2  centimeters  in  ductility  for  every  5  points 
in  penetration.  This  correction  is  only  an  approximate  one.  If  it 
becomes  necessary  to  soften  the  asphalt  under  examination  and 
to  bring  it  to  a  penetration  of  50  at  yy°  F.,  this  is  done  by  melting 
the  asphalt  at  a  temperature  of  approximately  300°  F.,  and 
thoroughly  incorporating  with  it,  while  in  the  molten  condition, 
sufficient  flux  or  residuum  to  bring  it  to  the  desired  consistency. 
The  flux  employed  should  preferably  be  that  to  which  it  is  pro- 
posed to  use  in  practice. 

The  ductility  test  is  then  made  on  the  mixture  of  asphalt  and 
flux  so  prepared. 

Si^e  of  Briquette. — The  dimensions  of  this  are  as  follows: 

Length  over  all  7^  centimeters 

Distance  between  clips   3       centimeters 

Width  at  mouth  of  clips 2      centimeters 

Width   at   minimum   cross    section,   halfway 

between  clips   i       centimeter 

Thickness  throughout    i       centimeter 

Rapidity  of  Pull. — For  ductilities  taken  at  /"/°  F.,  5  centimeters 
per  minute.  For  ductilities  taken  at  32°  F.,  }i  centimeter  per 
minute. 

Temperature. — For  ordinary  paving  work,  the  standard  tem- 
perature is  yy°  F.  For  special  work,  ductilities  are  sometimes 
taken  at  32°  F. 

Description  of  M01.D. 

The  Dow  form  of  briquette  mold  is  shown  below. 

After  numerous  trials,  this  form  of  briquette  was  adopted  as 
being  the  most  suitable.  Briquettes  of  other  forms,  including 
those  shaped  like  a  rod,  were  discarded  owing  to  the  lack  of 
homogeneity  in  some  bitumens  which  rendered  their  pull  very 


KNGINEJ^RING   CH15MISTRY  307 

irregular  unless  the  briquette  was  so  shaped  that  it  would  fail  at 


Fig.    56. 

some  one  definite  point  of  least  cross  section.     The  molds  are 
made  of  brass  and  are  in  four  pieces. 

Preparation  of  Briquette:. 

The  molding  of  the  briquette  may  be  done  as  follows :  The 
mold  should  be  placed  upon  a  brasb  plate.  To  prevent  the  asphalt 
from  adhering  to  the  plate  and  the  inner  side  of  the  two  remov- 
able pieces  of  the  mold,  a  and  o',  they  should  be  well  amal- 
gamated. The  different  pieces  of  the  mold  should  be  held  to- 
gether in  a  clamp  or  by  means  of  an  India  rubber  band. 

The  material  to  be  tested  is  poured  into  the  mold  while  in  a 
molten  state,  a  slight  excess  being  added  to  allow  for  shrinkage 
on  cooling.  After  the  briquette  is  nearly  cooled,  it  is  smoothed 
off  level  by  means  of  a  heated  palette  knife.  When  cooled,  the 
clamp  is  taken  off  and  the  two  side  pieces,  a  and  a',  removed, 
leaving  the  briquette  of  asphalt  firmly  attached  to  the  two  ends 
of  the  mold,  which  thus  serve  as  clips.  The  briquette  should 
then  be  immersed  in  water  maintained  at  the  required  tempera- 
ture for  at  least  30  minutes  or  until  the  whole  mass  of  bitumen 
is  at  that  temperature.  It  is  then  pulled  apart  as  described  above. 
Preliminary  Treatment  of  Asphalts. 

Different  asphalts  vary  considerably  in  purity  and  character 
of  bitumen.  Any  appreciable  amount  of  mineral  matter  or  inert 
bitumen  will  largely  affect  the  ductility,  and  for  this  reason  the 


308  DNGINEKRING   CHE:mISTRY 

test  should  be  made  on  materials  of  approximately  the  same 
purity  as  well  as  consistency.  Asphalts  to  be  examined  for 
ductility  are  therefore  usually  divided  into  three  classes  and  are 
given  a  preliminary  treatment  as  described  below,  depending 
upon  their  classification. 

1.  Asphalts  containing  over  96  per  cent,  of  bitumen  soluble  in 
carbon  disulphide  and  free  from  lumps  of  inert  bitumen. 

2.  Asphalts  containing  less  than  96  per  cent,  of  bitumen 
soluble  in  carbon  disulphide,  in  which  the  bitumen  is  homogene- 
ous, or  nearly  so,  i.  e.,  contains  no  lumps  of  inert  bitumen. 

3.  Asphalts  in  which  the  bitumen  is  not  homogeneous;  i.  e., 
containing  lumps  of  hard  bitumen  which,  although  soluble  in  car- 
bon disulphide,  are  insoluble  in  the  softer  bitumen,  even  in  a  mol- 
ten condition,  which  forms  part  of  the  bitumen  under  examination. 

Asphalts  coming  under  the  first  classification  need  no  prelim- 
inary treatment  other  than  softening  as  previously  described 
until  they  have  a  consistency  of  50  penetration  at  yy^  F. 

Asphalts  coming  under  the  second  classification  should  be 
subjected  to  the  following  treatment. 

Sufiicient  quantity  of  the  refined  hard  asphalt  to  yield  150 
grams  of  pure  bitumen  is  treated  with  chemically  pure  carbon 
disulphide  in  an  Erlenmeyer  flask.  After  standing  for  2  or 
3  hours;  the  flask  is  shaken  until  none  of  the  asphalt  is  seen 
adhering  to  the  sides  or  bottom  of  the  flask,  after  which  it  is 
set  aside  and  allowed  to  stand  24  hours.  The  solvent  is  then 
carefully  decanted  from  the  residue  into  a  second  flask.  The 
residue  is  again  treated  with  the  solvent,  shaken,  allowed  to 
subside,  and  decanted  as  before.  This  is  continued  until  the 
solvent  is  practically  colorless  or  of  a  light  straw  color.  The 
combined  solutions,  after  standing  at  least  24  hours  after  the 
last  addition  of  solution,  should  then  be  carefully  decanted  off 
and  the  solvent  distilled  until  only  sufiicient  remains  to  keep  the 
extracted  bitumen  liquid.  The  residue  is  then  poured  into  a 
large  evaporating  dish  and  as  much  of  the  remaining  solvent  as 
possible  evaporated  off  on  a  steam  bath.  To  facilitate  the  re- 
moval of  the  last  particles  of  carbon  disulphide  from  the  bitumen 
while  on  the  steam  bath,  it  should  be  stirred  from  time  to  time. 


ENGINEERING    CHEMISTRY  309 

After  this  treatment  on  the  steam  bath,  y^  to  i  cc.  of  water  should 
be  incorporated  into  the  bitumen  and  the  heating  continued  over 
a  burner  until  all  foaming  ceases,  after  which  the  dish  contain- 
ing the  bitumen  should  be  placed  in  a  hot  air  oven  and  kept  at 
300°  F.  for  30  minutes.  While  heating  the  extracted  bitumen 
over  the  burner,  it  should  be  stirred  constantly  with  a  ther- 
mometer, and  care  exercised  that  the  temperature  never  exceeds 
3CX)°  F.  The  extracted  bitumen  is  brought  to  a  consistency  of 
50  penetration  at  yy^  F.  by  the  addition  of  sufficient  flux,  and  is 
then  ready  for  testing. 

Carbon  disulphide  containing  an  excess  of  sulphur  must  be 
avoided,  as  with  certain  asphalts  this  sulphur  reacts  upon  them 
and  lowers  the  ductility  of  the  extracted  bitumen.  Where  the 
asphalt  under  examination  is  completely  soluble  in  chemically 
pure  benzole,  this  solvent  may  advantageously  be  substituted  for 
carbon  disulphide,  as  it  is  less  inflammable  and  is  less  liable  to 
reduce  the  ductility  of  the  extracted  bitumen. 

Asphalts  coming  under  the  third  classification  should  be 
treated  as  follows : 

The  asphalt,  asphalt  cement,  or  bitumen  is  heated  in  an  air 
bath  at  a  temperature  between  300°  F.  and  350°  F.,  together  with 
a  20-mesh  sieve  and  a  50-mesh  sieve.  When  the  material  is  in 
a  thoroughly  molten  condition,  it  is  first  strained  through  the 
heated  20-mesh  sieve  and  afterwards  through  the  heated  50- 
mesh  sieve.  The  molten  material  must  not  be  forced  through  the 
sieves,  but  must  run  through  by  gravity  alone. 

If  the  material  thus  obtained  contains  less  than  96  per  cent, 
of  bitumen  soluble  in  carbon  disulphide,  it  must  be  still  further 
purified  by  the  method  described  for  asphalts  coming  under  the 
second  classification;  otherwise  it  may  be  softened  with  flux  to 
the  proper  consistency  and  is  then  ready  for  testing. 
Volatilization  Test. 
Equipment. 
I  constant-temperature  hot-air  oven  with  rubber  tubing. 

1  thermo-regulator. 

2  chemical  thermometers  reading  from  — 10°  C.  to  250°  C. 
I  tin  box,  6  centimeters  in  diameter  by  2  centimeters  deep. 

I  analytical  balance,  capacity  100  grams,  sensitive  to  o.i  milligram. 


3io  ^nginehjring  chemistry 

Method. 

The  object  of  the  volatilization  test  is  to  determine  the  per- 
centage of  loss  which  the  material  undergoes  when  20  grams  in 
a  standard-sized  container  are  subjected  to  a  uniform  temperature 
of  163°  C.  for  5  hours,  and  also  to  ascertain  any  changes  in  the 
character  of  the  material  due  to  such  heating. 

The  oven  known  as  the  New  York  Testing  L^aboratory  oven, 
is  used  by  the  Office  of  Public  Roads,  although  any  other  form 
may  be  used  that  will  give  a  uniform  temperature  throughout  all 
parts  where  samples  are  placed.  The  bulb  of  one  of  the  ther- 
mometers is  immersed  in  a  sample  of  some  fluid,  non-volatile 
bitumen,  while  the  other  is  kept  in  air  at  the  same  level.  The 
first  thermometer  serves  to  show  the  temperature  of  the  samples 
during  the  test,  while  the  latter  gives  prompt  warning  of  any 
sudden  changes  in  temperature  due  to  irregularities  in  the  gas 
pressure,  etc. 

Before  making  the  test  the  interior  of  the  oven  should  show  a 
temperature  of  163°  C.  as  registered  by  the  thermometer  in  air. 
The  tin  box  is  accurately  weighed  after  carefully  wiping  with  a 
towel  to  remove  any  grease  or  dirt.  About  20  grams  of  the 
material  to  be  tested  is  then  placed  in  the  box.  The  material  may 
then  be  weighed  on  a  rough  balance,  if  one  is  at  hand,  after 
which  the  accurate  weight,  which  should  not  vary  more  than  0.2 
gram  from  the  specified  amount,  is  obtained.  It  may  be  necessary 
to  warm  some  of  the  material  in  order  to  handle  it  conveniently, 
after  which  it  must  be  allowed  to  cool  before  determining  the 
accurate  weight. 

The  sample  should  now  be  placed  in  the  oven,  where  it  is  al- 
lowed to  remain  for  a  period  of  5  hours,  during  which  time  the 
temperature  as  shown  by  the  thermometer  in  bitumen  should  not 
vary  at  any  time  more  than  2°  C.  from  163°  C.  The  sample  is 
then  removed  from  the  oven,  allowed  to  cool,  and  reweighed. 
From  the  difference  between  this  weight  and  the  total  weight 
before  heating,  the  percentage  of  loss  on  the  amount  of  material 
taken  is  calculated. 

The  general  appearance  of  the  residue  should  be  noted,  es- 
pecially with  regard  to  any  changes  which  the  material  may  have 


Engine;ering  chemistry  311 

undergone.  Some  relative  idea  of  the  amount  of  hardening  which 
has  taken  place  may  be  obtained  from  the  results  of  a  float  or 
penetration  test  made  on  the  residue,  as  compared  with  the  re- 
sults of  the  same  test  on  the  original  sample.  It  is  also  frequently 
desirable  to  make  the  specific  gravity  and  other  tests  on  the 
residue  for  the  purpose  of  identifying  or  ascertaining  the  char- 
acter of  the  base  used  in  the  preparation  of  cut-back  products. 
Before  any  tests  are  made  on  the  residue,  it  should  be  melted 
and  thoroughly  stirred  while  cooling. 

USK  OF  THE  VoivATlI.IZATlON  TDST. 

The  volatilization  test,  as  above  described,  is  made  on  prac- 
tically all  bitumens  with  the  exception  of  tars,  for  which  the  dis- 
tillation test  answers  a  similar  purpose.  The  test  is  also  fre- 
quently made  at  105°  C.  for  5  hours,  and  with  products  containing 
small  amounts  of  water  it  is  usually  necessary  to  make  a  test  at 
the  lower  temperature  before  the  material  can  be  heated  at  163°  C. 
without  foaming  over.  In  the  case  of  emulsions  it  is  customary 
to  determine  the  loss  on  a  20-gram  sample  at  room  temperature 
for  24  hours,  after  which  the  sample  is  heated  at  105°  C.  for  5 
hours.  This  additional  loss  is  obtained  and  all  determinations 
are  made  on  the  dried  residue  and  reported  accordingly. 

The  volatilization  test  is  also  occasionally  made  at  205°  C.  for 
5  hours  on  a  fresh  sample  in  order  to  show  the  effect  of  this 
higher  temperature  as  compared  with  the  results  at  163°  C. 

Determination  of  Flash  and  Burning  Points. 

Equipment. 
I  New  York  State  Board  of  Health  oil  tester  with  Bunsen  burner. 

(Fig.  57.) 
I  chemical  thermometer  reading  from  0°  C.  to  400°  C. 
I  piece  of  6-millimeter  glass  tubing,  6  centimeters  in  length,  one  end 
of   which   has   been   drawn   to   a    i -millimeter    opening.      Soft 
rubber  tubing  for  gas  connection. 

.Me:thod. 
While  for  all  ordinary  purposes  the  open-cup  method  of  de- 
termining the  flash  and  burning  points  of  bituminous  road  ma- 
terials is  sufficiently  accurate,  the  closed-up  method  described 
below  is  to  be  preferred. 


312 


ENGINEERING   CHEMISTRY 


The  oil  tester  shown  in  Fig.  57  consists  of  a  copper  oil  cup  a  of 
about  300  cc.  capacity,  which  is  heated  in  a  water  or  oil  bath 
by  a  small  Bunsen  flame.  The  cup  is  provided  with  a  glass  cover, 
carrying  a  thermometer,  and  a  hole  for  inserting  the  testing  flame. 
Ihe  testing  flame  is  obtained  from  a  jet  of  gas  passed  through 
the  piece  of  glass  tubing  and  should  be  about  5  millimeters  in 
length. 


Fig.  57. — N.  Y.    State  Tester. 

The  flash  test  is  made  as  follows :  The  oil  cup  should  first 
be  removed  and  the  bath  filled  with  water  or  cottonseed  oil.  The 
oil  may  always  be  used  and  is  necessary  for  bitumens  flashing  at 
a  temperature  of  over  100°  C.  The  oil  cup  should  be  replaced 
and  filled  with  the  material  to  be  tested  to  within  3  millimeters  of 
the  flange  joining  the  cup  and  the  vapor  chamber  above.  The 
glass  cover  is  then  placed  on  the  oil  cup  and  the  thermometer  so 
adjusted  that  its  bulb  is  just  covered  by  the  bituminous  material. 


ENGINEERING   CHEMISTRY  313 

r 

The  Bunsen  flame  should  be  appUed  in  such  a  manner  that  the 
temperature  of  the  material  in  the  cup  is  raised  at  the  rate  of 
about  5°  C.  per  minute.  From  time  to  time  the  testing  flame  is 
inserted  in  the  opening  in  the  cover  to  about  half  way  between 
the  surface  of  the  material  and  the  cover.  The  appearance  of  a 
faint  bluish  flame  over  the  entire  surface  of  the  bitumen  shows 
that  the  flash  point  has  been  reached  and  the  temperature  at  this 
point  is  taken. 

The  burning  point  of  the  material  may  now  be  obtained  by  re- 
moving the  glass  cover  and  replacing  the  thermometer  in  a  wire 
frame.  The  temperature  is  raised  at  the  same  rate  and  the 
material  tested  as  before.  The  temperature  at  which  the  material 
ignites  and  burns  is  taken  as  the  burning  point. 

At  the  conclusion  of  this  test  the  flame  should  not  be  blown  out 
for  danger  of  splashing  the  hot  material.  A  metal  cover  or  ex- 
tinguisher should  be  employed  for  this  purpose  by  placing  it  over 
the  ignited  material. 

Melting  Point  Determination. 

Equipment. 
I  iron  tripod. 

I  Bunsen  burner  and  tubing. 
I  piece  of  wire  gauze  10  centimeters  square. 
I  800  cc.  Jena  glass  beaker,  low  form. 
I  400  cc.  Jena  glass  beaker,  tall,  without  lip. 
I  iron  ring  support    (ring  7.5  centimeters  in  diameter)    and  burette 

clamp. 
I  metal  cover. 
I  object  glass. 
I  piece  of  wire   (No.  12  Brown  &  Sharpe  gauge)   20  centimeters  in 

length,  bent. 
I  chemical  thermometer  reading  from  0°  C.  to  250°  C. 
I  cubical  brass  mold. 
I  large  metal  kitchen  spoon. 
I  steel  spatula. 

Method. 
Since  bitumens  are  mixtures  of  various  organic  compounds, 
they  can  have  no  true  melting  point,  but  an  arbitrary  method  for 
determining  the  so-called  melting  point  of  these  materials  sufli- 


314  ENGINEERING   CHEMISTRY 

ciently  solid  to  maintain  their  form  for  some  time  under  normal 
conditions  is  of  value  as  a  means  of  identification  and  for  control 
work.  A  number  of  methods  have  been  tried,  but  the  following 
has  been  selected  as  the  most  convenient  and  accurate  for  such 
materials. 

The  material  under  examination  is  first  melted  in  the  spoon 
by  the  gentle  application  of  heat  until  sufficiently  fluid  to 
pour  readily.  Care  must  be  taken  that  it  suffers  no  appreciable 
loss  by  volatilization.  It  is  then  poured  into  the  ^^-inch  brass 
:ubical  mold,  which  has  been  amalgamated  with  mercury  and 
which  is  placed  on  an  amalgamated  brass  plate.  The  brass  may 
be  amalgamated  by  washing  it  first  with  a  dilute  solution  of 
mercuric  chloride  or  nitrate,  after  which  the  mercury  is  rubbed 
into  the  surface.  By  this  means  the  bitumen  is,  to  a  considerable 
extent,  prevented  from  sticking  to  the  sides  of  the  mold.  The 
hot  material  should  slightly  more  than  fill  the  mold  and,  when 
cooled,  the  excess  may  be  cut  off  with  a  hot  spatula. 

After  cooling  to  room  temperature,  the  cube  is  removed  from 
the  mold  and  fastened  upon  the  lower  arm  of  a  No.  12  wire 
(Brown  &  Sharpe  gauge)  bent  at  right  angles  and  suspended 
beside  a  thermometer  in  a  covered  Jena  glass  beaker  of  400  cc. 
capacity,  which  is  placed  in  a  water  bath,  or,  for  high  tempera- 
tures, a  cotton  seed  oil  bath.  The  wire  should  be  passed  through 
the  center  of  two  opposite  faces  of  the  cube,  which  is  suspended 
with  its  base  i  inch  above  the  bottom  of  the  beaker.  The  water 
or  oil  bath  consists  of  an  800  cc.  low-form  Jena  glass  beaker 
suitably  mounted  for  the  application  of  heat  from  below.  The 
beaker  in  which  the  cube  is  suspended  is  of  the  tall-form  Jena 
type  without  lip.  The  metal  cover  has  two  openings.  A  cork, 
through  which  passes  the  upper  arm  of  the  wire,  is  inserted  in 
one  hole  and  the  thermometer  in  the  other.  The  bulb  of  the 
thermometer  should  be  just  level  with  the  cube  and  at  an  equal 
distance  from  the  side  of  the  beaker.  In  order  that  a  reading  of 
the  thermometer  may  be  made,  if  necessary,  at  the  point  which 
passes  through  the  cover,  the  hole  is  made  triangular  in  shape 
and  covered  with  an  ordinary  object  glass  through  which  the  stem 


ENGINEERING   CHEMISTRY  315 

of  the  thermometer  may  be  seen.  Readings  made  through  this 
glass  should  be  calibrated  to  the  angle  of  observation,  which  may 
be  made  constant  by  always  sighting  from  the  front  edge  of  the 
opening  to  any  given  point  on  the  stem  of  the  thermometer  below 
the  cover. 

After  the  test  specimen  has  been  placed  in  the  apparatus,  the 
liquid  in  the  outer  vessel  is  heated  in  such  a  manner  that  the 
thermometer  registers  an  increase  of  5°  C.  per  minute.  The  tem- 
perature at  which  the  bitumen  touches  a  piece  of  paper  placed  in 
the  bottom  of  the  beaker  is  taken  as  the  melting  point.  Deter- 
minations made  in  the  manner  described  should  not  vary  more 
than  2°  for  different  tests  of  the  same  material.  At  the  beginning 
of  this  test  the  temperature  of  both  bitumen  and  bath  should  be 
approximately  25°  C. 

Use  op  MeivTing  Point  Determination. 

The  melting-point  determination  should  be  made  on  all  bi- 
tuminous road  binders  sufficiently  hard  to  be  handled  at  room 
temperature  after  removing  from  the  mold.  This  test  is  not 
usually  required  for  bitumens  which  are  to  be  cut  with  a  non- 
volatile flux  before  use. 

The  Extraction  of  Bituminous  Aggregates. 

Equipment  for  Recovering  Aggregate  Oni.y. 

I  centrifuge   extractor,   complete   with   motor,    speed    regulator,    and 

electrical  connections.     (Fig.  58.) 
I  hot  plate. 
I  enamel  ware  dish   approximately  2   inches   deep   and   9  inches   in 

diameter. 
I  hammer. 
I  ^-inch  cold  chisel, 
I  large  metal  kitchen  spoon. 
I  square  foot  of  i /16-inch  deadening  felt  paper. 
I  i>4-inch  stiff  flat  brush. 
I  500  cc.  bottle  or  flask. 

I  balance,  capacity  i  kilogram,  sensitive  to  o.i  gram. 
I  sheet  of  heavy  Manila  paper. 


3i6 


ENGINEJERING   CHEMISTRY 


Additional  Equipment  for  Recovering  Bitumen. 
I  iron  ring  support  (ring  lo  centimeters  in  diameter). 
I  iron  ring  support  with  condenser  clamp. 

I  round  tin  can,  lo  by  12  centimeters,  covered  with  asbestos  paper. 
I  32  candle-power  incandescent  lamp,  with  socket  and  connections. 
I  asbestos  hood.     (Fig.  59.) 
I   1,000  cc.  round-bottom  flask,  with  cork. 

I  spiral  condenser,  length  of  body  25  centimeters,  with  cork  to  fit,  and 
rubber  tubing  connections. 
50  centimeters  of  glass  tubing,  8  millimeters  bore. 
I  1,000  cc.  flat-bottom  flask. 

I  porcelain  evaporating  dish,  11  centimeters  in  diameter. 
I  watch  glass,  20  centimeters  in  diameter. 
I  steam  bath. 

Method. 
The  extractor  shown  in  Fig.  58  was  designed  upon  lines  sitg- 


/• 

^ 

X 

h'-' 

Tp^ 

----.-4 

—y 

1. 

Fig.   58. — Office  of  Public   Roads  centrifuge  extractor    (Reeve   type). 


gested  by  an  examination  of  machines  in  use  by  A.  E.  Schutte  and 
C.  N.  Forrest.  It  consists  of  a  ^5 -horse-power  1,100  revolutions 
per  minute  vertical-shaft  electric  motor  a,  with  the  shaft  project- 


ENGINEERING   CHEMISTRY  317 

ing  into  the  cylindrical  copper  box  b,  the  bottom  of  which  is  so 
inclined  as  to  drain  to  the  spout  c.  A  ^/j^Q-inch  circular  brass 
plate  9^  inches  in  diameter  is  shown  in  d,  and  upon  this  rests 
the  sheet-iron  bowl  e,  which  is  8^  inches  in  diameter  by  2  ^/^g 
inches  high,  and  has  a  2-inch  circular  hole  in  the  top.  Fastened 
to  the  inner  side  of  the  bowl  is  the  brass  cup  /,  having  a  circle  of 
^8-inch  holes  for  the  admission  of  the  solvent,  and  terminating 
in  the  hollow  axle,  which  fits  snugly  through  a  hole  at  the  center 
of  the  brass  plate.  The  bowl  may  be  drawn  firmly  against  a  felt- 
paper  ring  g,  ^-inch  wide,  by  means  of  the  2^-inch  milled  nut  h, 
for  which  the  hollow  axle  is  threaded  for  a  distance  of  ^  inch 
directly  below  the  upper  surface  of  the  plate.  The  axle  fits  snugly 
over  the  shaft  of  the  motor,  to  which  it  is  locked  by  a  slot  and 
cross  pin  i. 

The  aggregate  is  prepared  for  analysis  by  heating  it  in  enamel- 
ware  pan  on  the  hot  plate  until  it  is  sufficiently  soft  to  be 
thoroughly  disintegrated  by  means  of  a  large  spoon.  Care  must 
be  taken,  however,  that  the  individual  particles  are  not  crushed. 
If  a  section  of  pavement  is  under  examination,  a  piece  weigh- 
ing somewhat  over  i  kilogram  may  be  cut  off  with  hammer  and 
chisel.  The  disintegrated  aggregate  is  then  allowed  to  cool, 
after  which  a  sufficient  amount  is  taken  to  yield  on  extraction 
from  50  to  60  grams  of  bitumen.  It  is  placed  in  the  iron  bowl 
and  a  ring  ^4 -inch  wide,  cut  from  the  felt  paper,  is  fitted  on 
the  rim,  after  which  the  brass  plate  is  placed  in  position  and 
drawn  down  tightly  by  means  of  the  milled  nut.  If  the  bitumen 
is  to  be  recovered  and  examined,  the  felt  ring  should  be  prev- 
iously treated  in  the  empty  extractor  with  a  couple  of  charges  of 
carbon  disulphide  in  order  to  remove  any  small  amount  of 
grease  or  resin  that  may  be  present,  although  a  proper  grade  of 
felt  should  be  practically  free  from  such  products.  The  bowl 
is  now  placed  on  the  motor  shaft  and  the  slot  and  pin  are  care- 
fully locked.  An  empty  bottle  is  placed  under  the  spout  and 
150  cc.  of  carbon  disulphide  is  poured  into  the  bowl  through  the 
small  holes.  The  cover  is  put  on  the  copper  box  and,  after 
allowing  the  material  to  digest  for  a  few  minutes,  the  motor  is 


3l8  DNGINKEJRING   CHElMISTRY 

Started,  slowly  at  first  in  order  to  permit  the  aggregate  to  dis- 
tribute uniformly.  The  speed  should  then  be  increased  suf- 
ficiently by  means  of  the  regulator  to  cause  the  dissolved  bitumen 
to  flow  from  the  spout  in  a  thin  stream.  When  the  first  charge 
has  drained,  the  motor  is  stopped  and  a  fresh  portion  of  disul- 
phide  is  added.  This  operation  is  repeated  from  four  to  six  times 
with  150  cc.  of  disulphide.  With  a  little  experience  the  operator 
can  soon  gauge  exactly  what  treatment  is  necessary  for  any 
given  material.  When  the  last  addition  of  solvent  has  drained 
off,  the  bowl  is  removed  and  placed  with  the  brass  plate  upper- 
most on  a  sheet  of  Manila  paper.  The  brass  plate  and  felt  ring 
are  carefully  laid  aside  on  the  paper  and,  when  the  aggregate  is 
thoroughly  dry,  it  can  be  brushed  on  a  pan  of  the  rough  balance 
and  weighed.  The  difference  between  this  weight  and  the  original 
weight  taken  shows  the  amount  of  bitumen  extracted.  The 
aggregate  may  then  be  tested  as  occasion  requires. 

When  it  is  desired  to  recover  and  examine  the  bitumen,  the 
apparatus  shown  in  Fig.  59  will  be  found  convenient  and  fairly 
safe  for  the  distillation  and  recovery  of  such  inflammable  sol- 
vents as  carbon  disulphide.  In  the  laboratory  of  the  Office  of 
Public  Roads  this  apparatus  is  arranged  so  that  the  glass  tubing 
passes  through  a  stone  partition  between  two  sections  of  a  small 
hood,  thus  keeping  the  distilling  and  receiving  apparatus  entirely 
separated. 

The  solution  of  bitumen  should  be  allowed  to  stand  overnight 
in  order  to  permit  the  settling  of  any  line  mineral  matter  that  is 
sometimes  carried  through  the  felt  ring  in  the  extractor.  The 
solution  is  then  decanted  into  the  flask  a,  and  the  solvent  is  driven 
off  by  means  of  heat  from  an  incandescent  lamp  until  the  residue 
is  of  a  thick  sirupy  consistency.  Meanwhile  the  solvent  is  con- 
densed and  recovered  in  the  flask  b.  The  residue  is  poured  into 
an  1 1 -centimeter  porcelain  evaporating  dish,  and  evaporated  on  a 
steam  bath.  The  most  scrupulous  care  must  be  taken  at  all 
times  that  no  flames  are  in  its  immediate  vicinity.  Evaporation 
is  carried  on  at  a  gentle  heat,  with  continual  stirring,  until  form- 
ing practically  ceases.     It  is  advisable  to  have  a  large  watch 


ENGINEiERING   CHEMISTRY 


319 


glass  at  hand  to  smother  the  flames  quickly,  should  the  material 
ignite.  As  the  foaming  subsides,  the  heat  of  the  steam  bath  may 
be  gradtially  raised,  and  evaporation  is  continued  until  the 
bubbles  beaten  or  stirred  to  the  surface  of  the  bitumen  fail  to 
give  a  blue  flame  or  odor  or  sulphur  dioxide  when  ignited  by  a 
small  gas  jet.     The  dish  of  bitumen  should  then  be  set  in  a  hot- 


Fig.   59. — Recovery  apparatus. 

air  oven  maintained  at  105°  C.  for  about  an  hour,  after  which 
it  is  allowed  to  cool.  Its  general  character  is  noted  and  any 
tests  for  bitumens  that  are  necessary  are  then  made  upon  it. 

Grading  the  Mineral  Aggp:egate. 

Equipment. 
I  set  of  18-inch  stone  sieves  with  meshes  of  i^,  1%,  1,  ^,  ]/2,  %,  and 

y^  inches,  respectively. 
I  set  of  8-inch  brass  sand  sieves  of   10,  20,  30,  40,   50,  80,   100,  and 

200-mesh,  respectively,  with  pan  and  cover. 
I  rough  balance,  capacity  i  kilogram,  sensitive  to  o.i  gram. 
I  ij^-inch  stiff  flat  brush 

Several  sheets  of  Manila  paper. 


320 


ENGINEERING   CHEMISTRY 


Fig.  60. — Dulin  Rotarex,  for  Determining  the  Mineral  Aggregate  in  Bitumen  Pave- 
ments. The  sample  may  be  observed  at  all  times  and  solvent  added  without 
removing  the  cover.  The  solvent  used  is  non-inflammable  and  time  for  extraction 
is  5  minutes,  leaving  mineral  aggregate  perfectly  dry  so  that  grades  may  be  deter- 
mined. Small  model  for  samples  of  10,  25  or  50  grams,  for  no  volts,  either  alter- 
nating or  direct  current   (except  25   cycles). 

Method. 

For  aggregates  containing  particles  too  large  to  pass  a  ^-inch 
screen,  the  stone  sieves  are  used,  and  are  stacked  in  their  regular 
order  over  a  sheet  of  heavy  paper,  with  the  largest  size  required 
on  top.  The  weighed  amount  of  stone  is  placed  on  the  largest 
sieve  and  is  carefully  protected  from  drafts  which  might  carry 
away  any  of  the  fine  material.  The  upper  sieve  is  then  removed 
from  the  stack  and  shaken  over  a  large  sheet  of  paper  until  no 
more  particles  come  through.  The  material  thus  retained,  in- 
cluding any  fragments  caught  in  the  meshes  of  the  sieve,  is 
weighed  and  that  which  passes  is  added  to  the  contents  of  the 
succeeding  sieve.  This  operation  is  repeated  with  each  succeed- 
ing sieve. 


ENGINEERING   CHEMISTRY 


321 


When  grading  sands  or  fine  aggregates,  it  is  customary  to  take 
a  100-gram  sample  in  order  that  the  weights  may  give  direct  per- 
centages to  tenths  of  i  per  cent.  The  sieves  are  stacked  in 
regular  order  with  the  200-mesh  sieve  resting  on  the  pan.  The 
sample  is  brushed  on  the  top  sieve,  after  which  the  cover  is  put 
on  and  the  stack  agitated  for  about  5  minutes  with  both  rocking 
and  circular  shaking.  Each  sieve  is  removed  in  order,  and  shaken 
and  tapped  on  a  clean  piece  of  paper  until  no  appreciable  amount 


^JJ^^^^S^   j  1 

■ 

K 

I^H 

Fig.   61.— Sieve   Shaker  with  Electric  Motor. 


of  material  comes  through.  All  lumps  are  broken  up  by  crushing 
them  against  the  side  of  the  sieve  with  the  finger  or  a  small 
spatula.  The  contents  of  the  sieve  are  emptied  into  the  pan  of 
the  balance.  All  particles  caught  in  the  mesh  are  removed  by 
brushing  across  the  underside  of  the  sieve  and  are  added  to  the 
contents  of  the  pan.  As  great  opportunity  exists  for  wide  var- 
iations in  the  results  of  sand  gradings  made  by  different  persons, 


322  Engine:e:ring  chemistry 

owing  to  the  possibility  of  always  getting  a  little  more  material  to 
pass  by  continued  shaking,  it  is  well  for  the  novice  to  repeat  his 
sifting  on  any  given  mesh,  after  having  weighed  it,  in  order  to 
see  what  further  loss  he  can  produce.  If  his  judgment  has  not 
erred,  several  minutes  further  sifting  should  not  produce  a  loss 
of  over  0.5  gram. 

Where  coarse  aggregates  have  considerable  material  passing  a 
^-inch  screen  and  it  is  desired  to  grade  this  material  further,  it 
should  be  weighed  and  well  mixed,  quartered,  if  necessary,  and  a 
100-gram  sample  should  be  passed  through  the  sand  sieves.  From 
the  percentages  so  obtained  and  the  weight  of  material  passing  the 
^-inch  sieve,  the  percentages  of  the  total  aggregate  which  these 
finer  materials  represent  may  be  calculated. 

The  Office  of  Public  Roads  has  adopted  the  following  recom- 
mendations of  the  Committee  on  Standard  Tests  for  Road  Ma- 
terials of  the  American  Society  for  Testing  Materials  as  to  the 
size  of  wire  for  standard  sand  sieves : 

Diameter  of  wire, 
Meshes  per  linear  inch:  inches. 

10  0.027 

20  0.0165 

30  0.01375 

40  0.01025 

50  0.009 

80  .0.00575 

100  0.0045 

200  0.00235 

Distillation  Test. 

Equipment. 
I  750  cc.  glass  retort  with  tiibulature. 
I  chemical  thermometer,  0°  C.  to  400°  C. 
6  25  cc.  glass  cylinders,  graduated  to  0.2  cc. 
I  iron  tripod. 

I  iron  support  with  condenser  clamp, 
I  iron  support  with  burette  clamp. 

1  piece  of  wire  gauze,  10  centimeters  square. 

2  Bunsen  burners. 
I  asbestos  hood. 

I  pint  tin  cup,  seamless. 

I  rough  balance,  capacity  i  kilogram,  sensitive  to  o.i  gram. 

I  analytical  balance,  capacity  100  grams,  sensitive  to  o.i  milligram. 


i:ngine:£:ring  chejmistry  323 

Me:thod. 

Briefly  described,  this  test  consists  in  distilling  250  cc.  of  the 
material  under  examination  in  a  750  cc.  glass  retort  at  a  uniform 
rate  of  from  40  to  60  drops  per  minute  and  collecting  the  various 
fractions  in  weighed  glass  graduates.  In  preparing  for  the  test 
it  will  be. found  convenient  to  mark  permanently  on  the  foot  of 
each  graduate  its  weight  to  within  o.i  gram.  Owing  to  the  pos- 
sibility of  varying  results  due  to  lack  of  uniformity  in  the  retorts, 
the  Office  of  Public  Roads  specifies  in  purchasing  that  "the  retorts 
shall  be  of  such  uniform  size  that,  when  placed  in  a  vertical  posi- 
tion with  the  bulb  and  mouth  of  stem  resting  on  a  level  surface,  it 
shall  require  not  less  than  725  nor  more  than  800  cc.  to  cause  an 
overflow  into  the  stem." 

The  retort  should  be  supported  with  the  tubulature  in  a  vertical 
position  on  one  pan  of  the  rough  balance  and  its  tare  accurately 
obtained. 

From  the  specific  gravity  of  the  tar  taken  at  25°  C,  the  weight 
of  250  cc.  is  calculated,  and  this  amount  after  warming  it  in  a 
tin  cup,  if  necessary,  to  make  it  sufficiently  fluid,  is  poured  into 
the  tared  retort.  A  cork  stopper  carrying  a  thermometer  is  then 
inserted  in  the  tubulature  so  that  the  top  of  the  bulb^  is  level  with 
the  bottom  of  the  juncture  of  the  stem  and  the  body  of  the  retort. 
A  cold,  wet  towel  wrapped  about  the  stem  of  the  retort  may  be 
made  to  serve  as  a  condenser  for  the  lighter  distillates.  The  tar 
should  be  heated  gradually  by  means  of  a  Bunsen  burner  and,  if  it 
is  a  crude  material  containing  much  water,  great  care  must  be 
taken  to  prevent  it  from  foaming  over.  When  the  thermometer 
registers  110°  C,  the  graduated  cylinder  containing  the  first  frac- 
tion is  replaced  by  another,  the  towel  is  removed,  and  the  asbestos 

^  It  was  formerly  the  practice  to  place  the  bottom  of  the  bulb  level  with  the  bottom 
of  the  juncture  of  the  stem  and  body  of  the  retort,  and  distillation  was  stopped  at 
^70°  C.  Recent  comparative  tests  have,  however,  shown  that  the  method  was  adopted 
gives  results  which  conform  more  closely  to  those  obtained  by  the  other  principal 
methods  in  use.  As  compared  with  the  former  method,  it  may  be  stated  that  the 
amount  of  total  distillate  to  315°  C.  is  approximately  the  same  as  that  obtained  at 
270°  C.  by  the  old  method.  The  adoption  as  a  standard  method  of  distillation  is  at 
present  being  considered  by  a  special  committee  of  the  American  Society  for  Testing 
Materials,  and  indications  point  to  the  fact  that  considerable  research  will  be  required 
both  with  regard  of  the  type  of  distilling  apparatus,  and  the  standardization  of  the  ther- 
mometer and  method  of  distillation  before  a  satisfactory  standard  can  be  recommended. 


324 


ENGINKERING    CHEMISTRY 


hood  placed  over  the  retort  to  prevent  radiation  to  insure  a  more 
uniform  temperature.  The  distillation  should  now  proceed  with- 
out difficulty,  and  the  rate  should  be  maintained  at  from  40  to  60 
drops  per  minute.  The  receiver  is  changed  again  at  170°  C, 
after  melting  down  by  gentle  heating  any  solid  material  that  may 
have  been  deposited  in  the  stem  of  the  retort.  The  next  fraction 
is  collected  up  to  270°  C,  using  as  many  graduated  cylinders  as 
may  be  necessary  without  allowing  any  to  become  filled  above  the 
25  cc.  mark.  The  last  fractions  is  collected  up  to  315°  C,  after 
which  the  burner  is  removed,  and  any  solid  matter  in  the  retort 
stem  is  melted  and  collected  in  the  last  cylinder. 

Any  solid  matter  adhering  to  the  sides  of  the  graduates  is 
melted  down  by  playing  the  flame  of  a  burner  upon  them,  after 
which  the  retort  and  graduates  are  cooled  to  room  temperature 
and  their  contents  determined  by  volume  and  weight.  The  vol- 
ume of  pitch  remaining  in  the  retort  is  found  by  deducting  the 
total  volume  of  the  distillates  from  the  original  250  cc.  taken.  If 
water  was  present  in  the  tar,  it  will  be  noticed  that  the  first  frac- 
tion separates  into  two  layers,  the  lower  of  ammoniacal  liquor  or 
water  and  the  upper  of  oil.  Note  should  be  made  of  the  approxi- 
mate volume  of  solids  which  precipitate  from  the  distillates  upon 
cooling. 

The  results  obtained  are  calculated  in  percentages  by  volume 
and  weight  to  tenths  of  i  per  cent,  and  reported  as  follows : 


Distillate 

Per  cent, 
by  volume 

Per  cent 
by  weight 

1.  Water  or  ammoniacal  liquid 

2.  First  light  oils  to  1 10°  C 

3.  Second  light  oils  1 10°  C 

4.  Heavy  oils  i7o°C.  to  270°  C 

■j;      Heavv  oils  270°  to  "^i  '^^  C 

— 

— 

f\        T'itpVi    rfiirJnf .     ... 

Use  of  thk  Distillation  Test. 

The  distillation  test  is  made  upon  tars  and  tar  products,  but 
seldom  upon  other  materials  unless  the  presence  of  tar  is  sus- 
pected, or  where  a  determination  of  water  is  required.     In  mak- 


ENGINEERING   CHEMISTRY  325 

ing  the  water  determinations  on  viscous  or  semi-solid  bituminous 
materials,  it  is  usually  advisable  to  render  the  samples  fluid  by 
the  addition  of  kerosene  or  benzol  before  distillation. 

Bitumens  and  Their  Essential  Constituents  for  Road 
Construction  and  Maintenance. 

So  much  confusion  exists  among  road  engineers  and  others  in- 
terested in  bituminous  road  binders  concerning  the  meaning  of 
certain  terms  as  applied  to  these  materials  that  it  has  seemed 
advisable  to  present  in  brief  form  the  definitions  of  such  terms 
as  at  present  used  by  the  United  States  Office  of  Public  Roads. 
It  should  be  understood,  however,  that  these  definitions  are  at 
present  more  or  less  arbitrary,  owing  to  wide  differences  of 
opinion  held  by  those  who  are  considered  authorities  on  the 
subject  of  bitumens.  Notwithstanding  these  facts,  it  is  hoped 
that  this  circular  will  furnish  highway  engineers  and  other  in- 
terested persons  with  a  foundation  for  acquiring  and  systemati- 
cally classifying  further  information  along  the  lines  herein  indi- 
cated. To  aid  them  in  this  matter  a  brief  discussion  of  the  value 
of  the  various  materials  used  in  road  construction  has  been  given 
in  addition  to  the  definitions. 

Acid  Sludge. — A  mixture  of  sulphonated  hydrocarbons  result- 
ing from  the  treatment  of  bitumens  with  sulphuric  acid;  usually 
a  waste  or  by-product  obtained  in  this  manner  from  the  purifica- 
tion of  tar  and  oil  distillates.  When  sufficiently  concentrated 
these  sulphonated  products  become  viscous  and  gummy.  They 
are  readily  attacked  by  water  and  are  therefore  unsuitable  for 
use  as  enduring  road  binders. 

Anthracene. — A  waxy  crystalline  hydrocarbon  having  the 
chemical  formula  Ci^Hjo,  found  in  tars,  principally  coal  tars 
which  have  been  produced  at  high  temperatures.  Anthracene  is 
believed  to  be  of  no  practical  value  in  road  binders. 

Artificial  Asphalt. — See  Asphalts  and  Oil  Asphalts. 

Artificial  Bitumens. — Hydrocarbon  distillates  and  residues 
produced  by  the  partial  or  fractional  distillation  of  bitumens, 
and  hydrocarbon  distillates  produced  by  the  destructive  distilla- 


326  enginke:ring  chemistry 

tion  of  bitumens,  pyro-bitumens,  and  other  organic  materials, 
such  as  wood,  bone,  etc.  Native  bitumens  which  have  been 
treated  merely  for  the  removal  of  water  and  extraneous  organic 
and  inorganic  materials  should  not  be  classed  as  artificial  prod- 
ucts, but  as  refined  native  bitumens. 

As pnmts.— Solid  or  semi-solid  native  bitumens,  consisting  of  a 
mixture  of  hydrocarbons  or  complex  structure,  largely  cyclic 
and  bridge  compounds,  together  with  a  small  proportion  of  their 
sulphur  and  nitrogen  derivatives,  but  free  from  any  appreciable 
amount  of  solid  paraffines,  melting  upon  the  application  of  heat 
and  evidently  produced  by  nature  from  petroleums  containing 
little  or  no  solid  paraffines.  Solid  or  semi-solid  residues  produced 
from  probably  similar  oils  by  artificial  processes  are  sometimes 
called  asphalts,  but  should  more  properly  be  termed  oil  asphalts. 
The  more  common  types  of  native  asphalts  are  known  by  the 
name  of  the  locality  in  which  they  occur,  such  as  Trinidad,  Ber- 
mudez,  Maracaibo,  Cuban,  California,  etc.  Native  asphalts  with 
few  exceptions  contain  water,  extraneous  organic  or  vegetable 
matter,  and  inorganic  matter,  such  as  clay,  sand,  etc.  A  large 
proportion  of  these  impurities  is  removed  by  a  rough  refining 
process  without  otherwise  changing  the  character  of  the  asphalt. 

Native  asphalts  are  usually  too  hard  to  be  used  as  road  binders 
without  first  fluxing  them  with  a  heavy  petroleum  residuum  and 
thus  producing  an  asphaltic  cement.  Artificial  asphalts  are,  as  a 
rule,  brought  to  suitable  consistency  during  the  process  of  manu- 
facture. 

Asphaltenes. — A  term  commonly  applied  to  those  hydrocar- 
bons in  petroleums,  petroleum  products,  malthas,  asphaltic  ce- 
ments, and  solid  native  bitumens  which  are  soluble  in  carbon 
bisulphide  but  insoluble  in  paraffine  naphtha.  As  a  rule  paraffine 
naphthas  of  different  specific  gravities  and  boiling  points  dis- 
solve different  amounts  of  hydrocarbons  in  a  given  bitumen,  and 
the  heavier  the  naphtha  and  the  higher  its  boiling  point  the 
greater  is  its  solvent  action.  It  is  evident,  therefore,  that  the 
percentage  of  asphaltenes  will  vary  with  the  gravity  and  boiling 
point  of  the  naphtha,  and  for  this  reason  it  would  seem  well  to 


ENGINEERING   CHEMISTRY  327 

substitute  for  the  term  asphalenes,  ''bitumen  insoluble  in  paraffine 
naphtha,"  with  a  statement  of  the  gravity  of  the  naphtha  used 
and  the  temperatures  between  which  it  boils.  The  presence  of 
naphtha  insoluble  hydrocarbons  is  supposed  to  give  body  to  the 
product  in  which  they  occur  and  to  be  accountable  to  a  great 
extent  for  its  binding  value.  They  show  no  binding  value,  since 
many  of  them  are  hard  and  brittle,  but  they  produce  adhesive 
mixtures  when  fluxed  with  certain  heavy  oils.  As  a  rule,  for  a 
given  type  of  bitumen  hardness  increases  with  the  percentage 
of  bitumen  insoluble  in  a  given  naphtha.  The  so-called 
asphaltenes  are  not  found  to  any  extent  in  native  bitumens  with 
a  paraffine  base,  but  occur  principally  in  asphalts,  malthas,  as- 
phaltic  petroleums,  and  in  blown  petroleum  residues.  They  vary 
chemically  and  physically  with  the  product  in  which  they  occur, 
and,  therefore,  do  not  represent  definite  chemical  compounds. 

Asphaltic  Petroleums. — Asphaltic  petroleums,  or  asphaltic  oils, 
are  petroleums  containing  an  asphaltic  base — i.  e.,  they  are 
capable  of  producing  residues  very  similar  to  native  asphalts  if 
evaporated  or  distilled  down  to  the  consistency  of  such  asphalts. 
They  contain  little  or  no  solid  paraffines  and  are  thus  differen- 
tiated from  paraffine  petroleums.  Native  asphalts  are  probably 
produced  from  such  oils  by  natural  processes. 

Asphaltic  Cement. — The  term  asphaltic  cement  was  originally 
applied  to  a  product  obtained  by  fluxing  an  asphalt  with  a  suf- 
ficient quantity  of  heavy  residual  oil  or  flux  to  produce  a  binder 
of  suitable  consistency  for  paving  purposes.  In  its  broadest  sense 
it  may  be  applied  to  all  semi-solid  bitumens  of  an  asphaltic  nature 
which  are  of  suitable  consistency  for  use  as  binders  in  street  or 
road  construction,  whether  prepared  by  fluxing  a  solid  native  or 
artificial  bitumen  or  by  reducing  an  asphaltic  or  semi-asphaltic 
petroleum  by  distillation  or  other  process. 

Baume  Gravity. — An  arbitrary  scale  of  specific  gravity  or 
density  of  liquids,  usually  expressed  as  degrees  Baume  or  °  B. 
This  scale  is  commonly  used  in  connection  with  oil  products. 
For  liquids  lighter  than  water  the  scale  begins  at  io°  B.,  which 
represents   the   specific   gravity   of   water,   or    i.oooo.      As   the 


328  ENGINEERING   CHEMISTRY 

Baume  degrees  increase  the  specific  gravity  decreases.  The  fol- 
lowing formulae  is  used  in  converting  Baume  degrees  for 
liquids  lighter  than  water  into  direct  specific  gravity  and  vice 
versa : 

Specific  gravity  =        ^^^o-g    at  17-5°  C. 

°B  = ^ ^  -130  at  17.5°  C.  ' 

Specific  gravity 

For  liquids  heavier  than  water  the  scale  begins  at  0°  B.,  which 
represents  the  specific  gravity  of  water,  or  i.ocxdo.  In  this  scale 
the  degrees  Baume  increase  with  the  specific  gravity.  The  fol- 
lowing formulae  is  used  in  converting  Baume  degrees  for  liquids 
heavier  than  water  into  direct  specific  gravity  and  vice  versa : 

Specific  gravity  =  ^      op     at  15.5°  C  : 

°B=i46  — -^ r^ :-    at  15.5°  C. 

Specific  gravity 

Benzol. — A  volatile  colorless  fluid  hydrocarbon  of  character- 
istic odor  having  the  chemical  formula  CjjHg.  It  occurs  mainly 
in  crude  coal  tars  and  water-gas  tars,  and  boils  at  80.4°  C,  so 
that  it  is  removed  in  the  first  fraction  when  these  tars  are  sub- 
jected to  the  process  of  distillation.  Benzol  is  an  active  solvent 
for  most  bitumens.  It  is  sometimes  called  benzene,  but  should 
not  be  confused  with  benzine,  which  is  the  term  applied  to  the 
lighter  and  more  volatile  fractions  of  petroleum. 

Bitumen. — Bitumens  are  mixtures  of  native  or  pyrogenetic 
hydrocarbons  and  their  derivatives,  which  may  be  gases,  liquids, 
viscous  liquids,  or  solids.  If  solids,  they  melt  more  or  less  readily 
upon  the  application  of  heat  and  are  soluble  in  carbon  bisulphide, 
chloroform,  and  similar  solvents.  They  may  be  divided  into 
two  main  classes — (i)  native  bitumens  and  (2)  artificial  bitu- 
mens. Bitumens,  being  mixtures  of  hydrocarbons,  can  have  no 
melting  point,  although  this  term  is  often  used  to  denote  the 
temperature  at  which  they  soften  sufficiently  to  flow. 


I^NGINEERING    CHEMISTRY  329 

Bituminous. — A  term  applied  not  only  to  materials  or  objects 
which  contain  bitumen,  such  as  bituminous  rock,  bituminous 
macadam,  etc.,  but  also  to  certain  pyro-bitumens,  such  as  bitu- 
minous coal,  which  give  rise  to  the  formation  of  bitumens  upon 
being  subjected  to  the  process  of  destructive  distillation. 

Blown  Petroleum. — Blown  petroleums,  which  are  often  called 
blown  oils,  are  petroleum  residuums  through  which  a  jet  of  air 
has  been  passed  during  or  just  after  distillation.  The  blowing 
process  causes  certain  chemical  reactions  of  a  complicated  nature 
to  take  place  and  results  in  thickening  or  increasing  the  con- 
sistency of  the  oil  to  an  extent  depending  upon  its  temperature 
and  the  amount  of  blowing  which  it  receives.  Semi-solid  and 
solid  products  are  thus  often  formed  from  fluid  residuums.  If 
the  oil  is  asphaltic  or  semi-asphaltic  in  nature,  asphaltic  cements 
may  be  produced  in  this  manner.  Blown  oils  are  characteristi- 
cally short  or  non-ductile  when  semi-solid,  although  they  may 
possess  considerable  binding  value  if  not  originally  of  a  paraffine 
nature.  Blowing  an  oil  usually  increases  its  percentage  of  hy- 
drocarbons insoluble  in  any  given  paraffine  naphtha. 

Carbenes. — A  term  commonly  applied  to  those  hydrocarbons 
in  petroleum,  petroleum  products,  malthas,  asphaltic  cements,  and 
solid  native  bitumens  which  are  soluble  in  carbon  bisulphide  but 
insoluble  in  carbon  tetrachloride.  The  presence  of  an  appreci- 
able amount  of  these  hydrocarbons  indicates  that  the  material  in 
which  they  occur  has  been  subjected  to  unnecessarily  high  tem- 
peratures. Cracked  oil  residuums  show  an  increase  in  carbenes 
in  proportion  to  the  extent  of  cracking  and  the  formation  of 
these  products  is  evidently  a  near  step  to  coking.  But  little  is 
known  of  their  effect  upon  the  value  of  a  bitumen  for  road 
construction,  but  they  are  generally  looked  upon  with  suspicion 
and,  in  certain  specifications  for  asphaltic  cements,  their  presence 
has  been  limited  to  a  low  percentage. 

Carbon  Bisulphide. — This  substance,  sometimes  called  carbon 
disulphide,  is  a  volatile  and  extremely  inflammable  compound  of 
carbon  and  sulphur,  boiling  ai  47°  C.  and  having  the  chemical 
formula  CSg.    Pure  carbon  bisulphide  is  a  colorless  mobile  liquid 


330  ENGINEERING   CHEMISTRY 

having  an  ethereal  odor.  It  is  one  of  the  most  active  solvents 
for  bitumens  and  is  commonly  employed  for  this  purpose  in  the 
determination  of  total  bitumen. 

Carbon  Tetrachloride. — A  volatile  non-inflammable  compound 
of  carbon  and  chlorine,  boiling  at  ^6°  C.  It  is  a  colorless  mobile 
liquid  with  an  odor  similar  to  that  of  chloroform,  to  which  it  is 
closely  related,  and  has  the  chemical  formula  CCI4.  It  is  an  ex- 
cellent solvent  for  bitumens,  but  is  not  usually  as  powerful  as 
carbon  bisulphide.  It  is  employed  in  bitumen  analysis  for  the 
determination  of  carbenes  or  hydrocarbons  soluble  in  carbon  bi- 
sulphide but  insoluble  in  carbon  tetrachloride. 

Coal  Tar. — A  mixture  of  hydrocarbon  distillates,  most  un- 
saturated ring  compounds,  produced  in  the  destructive  distillation 
of  coal.  Crude  coal  tar  is  a  black,  more  or  less  viscid  fluid  having 
a  gassy  odor  and  varying  in  specific  gravity  from  i.io  to  1.25  and 
sometimes  higher.  It  always  contains  a  certain  amount  of  am- 
moniacal  water  which  makes  it  unsuitable  for  use  as  a  road  binder. 
When  reduced  to  proper  consistency  by  distillation,  coal  tar 
makes  an  excellent  bituminous  road  binder,  providing  it  does  not 
carry  too  high  percentages  of  free  carbon  and  naphthalene.  The 
composition  of  coal  tar  varies  according  to  the  coal  from  which 
it  is  produced  and  the  method  of  distillation.  Tar  produced  at 
high  temperatures  contain  a  large  amount  of  free  carbon  and 
usually  run  high  in  naphthalene,  while  those  produced  at  low 
temperatures  carry  less  free  carbon  and  as  a  rule  less  naphthalene. 
Low  temperature  coal  tars  are  therefore  more  suitable  for  the 
preparation  of  road  binders. 

Coke-Oven  Tars. — Coal  tar  produced  from  by-product  coke 
ovens  in  the  manufacture  of  coke  from  bituminous  coal.  This 
process  of  coke  manufacture  is  essentially  the  same  as  that  of  coal 
gas.  Larger  charges  of  coal  are,  however,  carbonized  in  the 
former,  and  as  a  rule  carbonization  is  conducted  at  a  lower  tem- 
perature than  in  the  manufacture  of  coal  gas.  The  resulting  tar 
therefore  contains  a  smaller  amount  of  free  carbon,  averaging 
from  3  to  10  per  cent.,  and  is  better  suited  for  the  preparation  of 
road  binders  than  most  gas-house  coal  tars. 


Engine;e;ring  chemistry  331 

Cracked  Oil. — The  term  cracked  oil,  as  applied  to  road  binders, 
refers  to  petroleum  residuums  which  have  been  overheated  in  the 
process  of  manufacture.  Overheating  causes  a  breaking  down  of 
certain  constituents  of  the  oil,  which  results  first  in  the  formation 
of  carbenes  and  later  of  coke  or  free  carbon.  Badly  cracked 
residuums  are  believed  to  be  inferior  road  binders. 

Cracking. — The  process  of  breaking  down  a  hydrocarbon  mole- 
cule by  the  application  of  heat.  This  may  result  either  in  the 
formation  of  other  hydrocarbons  molecules,  at  least  one  of  which 
is  unsaturated  and  shows  a  higher  ratio  of  carbon  to  hydrogen 
than  the  original  molecule,  or  else  in  the  disruption  of  the  molecule 
into  its  elements,  hydrogen  and  carbon.  In  the  latter  case  the 
process  is  said  to  be  destructive.  The  more  volatile  and  chemi- 
cally stable  hydrocarbons  can  be  cracked  only  at  temperatures 
above  their  boiling  points.  In  the  distillation  of  oils  this  is  ac- 
complished by  causing  condensation  to  take  place  in  the  still  and 
allowing  the  condensed  oils  to  fall  back  into  the  residue,  the 
temperature  of  which  is  considerably  higher  than  their  boiling 
points.  In  carbureted  water-gas  manufacture,  oils  are  cracked 
by  vaporizing  them  at  a  much  higher  temperature  than  their  boil- 
ing points.  The  heavier  oils  will,  however,  crack  at  temperatures 
below  their  normal  boiling  points,  and  this  is  particularly  true  of 
asphaltic  oils,  which  have  to  be  distilled  very  carefully,  some- 
times under  reduced  pressure,  in  order  to  produce  residuums 
which  are  not  cracked. 

Cut-Back  Products. — Petroleum  or  tar  residuums  which  are 
cut-back,  or  fluxed,  to  the  desired  consistency  with  a  distillate. 
Volatile  distillates  are  employed  for  this  purpose  in  the  prepara- 
tion of  road  binders,  when  it  is  desired  to  have  the  binder  in- 
crease in  consistency  or  become  harder  after  application.  In 
such  cases  a  residuum  of  proper  consistency  for  a  road  binder  is 
cut-back  merely  for  the  purpose  of  facilitating  application. 

Dead  Oils. — Heavy  oils  distilled  from  tars  at  between  170°  and 
270°  C.  with  a  density  greater  than  water.  These  oils,  if  free 
from  naphthalene,  serve  as  an  excellent  flux  in  the  preparation 


332  ENGINEERING   CHEMISTRY 

of  cut-back  road  binders  from  tar  pitches,  which  are  too  brittle 
for  this  purpose. 

Destructive  Distillation. — A  process  of  distilling  organic 
materials  in  which  the  identity  of  the  material  distilled  is  de- 
stroyed, resulting  in  the  formation  of  tarry  distillates  and  a  coke 
residue. 

Dehydrated  Tar. — Crude  tar  from  which  all  water  has  been 
removed  by  distillation  and  mechanical  contrivances  known  as 
separators. 

Bmidsions. — Oily  substances  made  miscible  with  water  through 
the  action  of  a  saponifying  agent  or  soap.  Petroleums  and  tars 
may  be  emulsified  by  this  means  and  such  emulsions,  if  properly 
prepared  from  good  materials,  are  often  serviceable  in  the  treat- 
ment of  roads.  The  majority  of  road  emulsions  can  be  consid- 
ered only  as  dust  palliatives  and  temporary  binders. 

Fixed  Carbon. — The  residual  coke  obtained  upon  burning  hy- 
drocarbon products  in  a  covered  vessel  in  the  absence  of  free 
oxygen,  according  to  an  arbitrary  method.  As  applied  to 
bituminous  road  materials,  the  determination  of  fixed  carbon 
would  seem  to  be  of  value  in  connection  with  petroleum  and 
asphaltic  products  only.  Paraffine  hydrocarbons  produce  little  or 
no  fixed  carbon,  while  those  of  asphaltic  character  show  a  very 
considerable  amount,  depending  upon  the  percentage  of  asphaltic 
compounds  present  and  the  consistency  of  the  material.  The 
fixed  carbon  determination,  therefore,  indicates  the  mechanical 
stability  and  body  of  such  materials.  It  is  not,  however,  an  ex- 
tremely accurate  determination  and  should  not  be  too  strongly 
relied  upon.  Since  fixed  carbon  is  a  product  formed  by  ignition, 
it  should  not  be  confused  with  free  carbon,  which  is  a  material 
already  existing  in  suspension.  The  presence  of  any  considerable 
quantity  of  free  carbon  vitiates  a  fixed  carbon  determination. 

Flux. — As  applied  to  road  binders,  this  term  covers  fluid  oils 
and  tars  which  are  incorporated  with  asphalts  and  semi-solid  or 
solid  oil  and  tar  residuums  for  the  purpose  of  reducing  their  con- 
sistency. Fluid  petroleum  residuums  are  commonly  employed  as 
fluxes  in  the  preparation  of  asphaltic  cements.    A  good  flux  pro- 


ENGINEERING   CHEMISTRY  333 

duces  an  absolutely  homogeneous  bituminous  mixture.  Both 
petroleum  and  tar  fluxes  will  produce  such  mixtures  with  native 
and  artificial  asphalts,  but  most  fluid  petroleum  products  will  not 
flux  tar  pitches  satisfactorily. 

Free  Carbon. — ^Organic  matter  in  tars  which  is  insoluble  in 
carbon  bisulphide.  It  has  no  binding  value  and  serves  no  useful 
purpose  in  a  road  binder  other  than  to  act  as  a  filler.  It  gives 
the  tar  in  which  it  occurs  a  false  consistency,  reduces  the  binding 
capacity  of  the  tar,  and  probably  interferes  with  its  penetration 
into  and  absorption  by  the  road  stone  or  road  surface.  The 
maximum  allowable  limit  of  free  carbon  in  road  binders  would 
seem  to  be  about  20  per  cent. 

Gas-House  Coal  Tar. — Coal  tar  produced  as  a  by-product  in 
the  manufacture  of  illuminating  gas  from  coal.  The  modern 
gas-house  coal  tar  is  usually  produced  at  high  temperatures  and, 
therefore,  carries  a  percentage  of  free  carbon  varying  from  20 
to  30  per  cent,  and  higher.  Unless  it  is  produced  at  low  or 
medium  temperatures  and  contains  less  than  20  per  cent,  free 
carbon,  it  is  not  well  suited  for  the  preparation  of  a  dust  palliative 
or  road  binder  by  direct  distillation.  High-carbon  tars  may, 
however,  be  combined  with  low-carbon  tars  in  such  proportion 
as  to  produce,  when  distilled  to  proper  consistency,  excellent  road 
binders  carrying  less  than  20  per  cent,  free  carbon. 

Gilsonite. — A  very  pure  solid  native  bitumen  possessing  many 
of  the  characteristics  of  asphalt.  It  differs  from  most  of  the 
native  asphalts  by  being  more  brittle,  having  a  higher  melting  or 
softening  point,  and  being  much  less  soluble  in  86°  B.  paraffine 
naphtha.  When  fluxed  with  certain  petroleum  residuums  it  pro- 
duces excellent  asphaltic  cements.  In  the  preparation  of  road 
binders  it  is  extensively  used  for  the  purpose  of  reinforcing 
blown  oils,  with  which  it  combines  to  form  rubbery  semi-solid 
mixtures.  Such  preparations  are  sometimes  termed  mineral 
rubber. 

Grahamite. — A  pure  solid  native  bitumen,  black  and  brittle, 
which  does  not  melt  readily,  but  intumesces  at  high  temperatures. 
It  is  differentiated  from  gilsonite  and  the  native  asphalts  by  the 


334  ENGINEJERING   CHEMISTRY 

fact  that  it  is  almost  insoluble  in  paraffine  naphtha.  It  has  been 
produced  at  high  temperatures,  as  evidenced  by  the  percentage 
of  carbenes  which  it  contains,  and  some  varieties  closely  approach 
the  pyrobitumens  in  characteristics.  It  has  been  used  to  some 
extent  in  the  preparation  of  asphaltic  cements,  but  up  to  the 
present  has  been  little  used  in  the  manufacture  of  road  binders. 

High-Carbon  Tars. — Tars  containing  a  high  percentage  of  free 
carbon — above  20  per  cent.  High-carbon  tars  are  produced  at 
high  temperatures  during  the  destructive  distillation  of  coal  and 
are  of  inferior  quality  for  use  as  dust  palliatives  and  road  binders. 

Hydrocarbons. — Chemical  compounds  composed  of  the  ele- 
ments hydrogen  and  carbon.  There  is  practically  an  unlimited 
number  of  such  compounds,  which  vary  greatly  in  physical  and 
chemical  characteristics.  Complex  mixtures  of  hydrocarbons 
constitute  by  far  the  greater  proportion  of  all  bitumens. 

Low-Carbon  Tars. — Tars  containing  a  low  percentage  of  free 
carbon — less  than  10  per  cent.  Low-carbon  tars  are  produced  at 
comparatively  low  temperatures  during  the  destructive  distilla- 
tion of  coal,  and  also  by  cracking  oil  vapors  during  the  manu- 
facture of  carbureted  water  gas.  As  a  rule  they  are  more  suitable 
than  high-carbon  tars  for  use  as  dust  palliatives  and  road  binders, 
or  for  the  preparation  of  such  substances. 

Malthas. — Malthas  are  very  viscous  semi-asphaltic  or  asphaltic 
native  bitumens  holding  an  intermediate  position  between  the 
petroleums  of  an  asphaltic  nature  and  the  native  asphalts.  As 
a  rule  they  possess  excellent  binding  properties.  They  constitute 
the  binding  material  of  many  bituminous  rocks  or  rock  asphalts, 
and  in  this  capacity  often  serve  as  valuable  road  binders.  Many 
malthas  have  a  tendency  to  harden  rapidly  when  exposed  to 
atmospheric  conditions,  and  this  property,  while  accountable  for 
an  increase  in  binding  value,  makes  them  unsuitable  for  use  as 
a  flux  in  the  preparation  of  asphaltic  cements. 

Malthenes. — A  term  commonly  applied  to  those  hydrocarbons 
in  petroleum,  petroleum  products,  malthas,  asphaltic  cements,  and 
solid  native  bitumens  soluble  in  both  carbon  bisulphide  and  par- 
afline  naphtha,  but  not  readily  volatile  at  temperatures  lower  than 


ENGINEERING   CHEMISTRY  335 

163°  C.  (325°  F.).  This  class  of  hydrocarbons  serves  as  a  valu- 
able permanent  fluxing  medium  for  the  so-called  asphaltenes  or 
naphtha  insoluble  bitumen  in  asphaltic  cements,  giving  the  cement 
any  desired  degree  of  softness  when  present  in  the  right  amount. 
It  is  evident,  therefore,  that  the  consistency  of  asphaltic  bitumens, 
and  particularly  stable  asphaltic  cements,  is  largely  dependent 
upon  the  relative  proportion  of  naphtha  soluble  and  naphtha  in- 
soluble hydrocarbons.  The  same  objection  to  the  use  of  the 
term  ''asphaltenes"  applies  to  the  use  of  the  term  "malthenes." 

Mineral  Rubber. — A  term  sometimes  applied  to  artificial  bitu- 
mens of  rubbery  consistency,  usually  composed  of  a  mixture  of 
gilsonite  and  blown  petroleum  residuum. 

Naphthas. — Mixtures  of  hydrocarbons  of  low  boiling  points 
occurring  rarely  in  nature,  commonly  obtained  from  the  frac- 
tional distillation  of  certain  bitumens.  When  this  term  is  applied 
to  low-boiling  coal  tar  distillates,  it  is  usually  prefixed  by  the 
words  "coal  tar."  The  word  "naphtha"  by  itself  is  generally 
applied  to  low-boiling  petroleum  products.  Different  grades  of 
naphtha  are  differentiated  not  only  by  their  boiling  points  but  also 
by  their  specific  gravities,  which  are  commonly  given  in  Baume 
degrees.  Those  of  very  low  boiling  points  and  specific  gravities 
are  called  petrolic  ethers.  Naphthas  vary  not  onl)  in  the  two 
properties  above  mentioned  but  also  with  the  type  of  petroleum 
from  which  they  are  obtained.  Those  derived  from  paraffine 
petroleums  are  quite  different  chemically  from  naphthas  obtained 
from  asphaltic  petroleums.  The  former  are  much  less  powerful 
solvents  for  asphaltic  substances  than  the  latter.  Paraffine  naph- 
tha is  used  as  a  solvent  for  the  separation  of  certain  classes  of 
hydrocarbons  in  asphaltic  substances. 

Naphthalene. — A  solid  crystalline  highly  volatile  hydrocarbon 
occurring  principally  in  coal  tars  and  having  the  chemical  for- 
mula CioHg.  Its  presence  in  excessive  quantities  in  road  tars  is 
believed  to  be  detrimental,  as  it  possesses  no  binding  value  and 
gradually  volatilizes  from  the  tar,  leaving  it  hard  and  brittle. 

Native  Bitumens. — Mixtures  of  hydrocarbons  occurring  in 
nature,  which  may  be  gases,  liquids,  viscous  liquids,  or  solids, 


336  ENGINEERING    CHEMISTRY 

but  if  solid  melting  more  or  less  readily  upon  the  application  of 
heat  and  dissolving  in  carbon  bisulphide,  chloroform,  and  similar 
solvents.  The  native  bitumens  that  are  of  use  as  road  materials 
are  petroleums,  malthas,  asphalts,  and  other  solid  products  such 
as  gilsonite  and  grahamite.  Native  bitumens  often  contain  im- 
purities such  as  water,  inorganic  matter  in  the  form  of  clay,  silt 
sand,  etc.,  and  extraneous  organic  or  vegetable  matter. 

Oil  Asphalts. — Artificial  oil  pitches  or  asphaltic  cements  pro- 
duced as  a  residuum  in  the  distillation  of  semi-asphaltic  and  as- 
phaltic petroleum.  Many  of  these  products  are  blown  and  are 
therefore  known  as  blown  oils. 

Oil  Pitches. — More  or  less  hard  oil  asphalts. 

Oil  Tars. — Mixtures  of  hydrocarbon  distillates,  mostly  un- 
saturated ring  compounds,  produced  in  the  cracking  of  oil  vapors 
at  high  temperatures.  Oil  tars  are  usually  by-products  of  the 
manufacture  of  oil  gas  or  carbureted  water  gas. 

Paraffine  Naphthas. — Naphthas  consisting  of  a  mixture  of  light 
volatile  hydrocarbons  of  the  paraffine  series,  ordinarily  obtained 
as  light  distillates  of  paraffine  petroleum. 

Paraffine  Petroleum. — Petroleum  the  base  of  which  is  com- 
posed principally  of  the  paraffine  or  open-chain  series  of  hydro- 
carbons ;  it  is  thus  differentiated  from  asphaltic  petroleums  which 
are  composed  largely  of  cyclic  or  ring  hydrocarbons.  Paraffine 
petroleums  and  the  unaltered  residues  produced  by  their  distilla- 
tion are  of  inferior  value  as  dust  palliatives  and  road  binders. 

Paraffine  Scale. — Solid  paraffines  recovered  by  distillation  and 
precipitation  of  the  distillates  of  petroleum  and  similar  materials. 
The  percentage  of  paraffine  in  bitumen  is  usually  determined  in 
this  manner. 

Paraffine. — The  term  paraffine  covers  a  number  of  greasy 
crystalline  hydrocarbons  of  the  paraffine  series  occurring  as  dis- 
solved wax  in  certain  classes  of  petroleiim.  When  these  products 
are  recovered  from  petroleum,  they  constitute  the  commercial 
product  paraffine.  Paraffine  is  believed  to  be  detrimental  to  road 
binders  in  which  it  occurs,  and  it  is  certain  that  its  presence  in 
excessive  amounts  indicates  inferiority  in  the  binding  value  of  the 


e;ngine;e;ring  che;mistry  337 

material.  It  is  probable,  however,  that  heavy  liquid  hydrocarbons 
of  the  same  chemical  series  as  solid  paraffine  exert  a  much  more 
injurious  effect. 

Petrolenes. — An  ambiguous  term  sometimes  applied  to  those 
hydrocarbons  described  under  malthenes,  which  are  soluble  in 
carbon  bisulphide  but  insoluble  in  paraffine  naphtha,  and  some- 
times to  hydrocarbons  in  petroleum  products  volatile  at  or  below 
163°  C.  (325°  F.).  Owing  to  misconceptions  which  may  occur, 
it  would  seem  advisable  to  eliminate  the  use  of  this  term. 

Petroleums. — Petroleums,  or  mineral  oils,  are  fluid  native  bitu- 
mens of  variable  composition,  depending  largely  upon  the  locality 
in  which  they  occur.  There  are  three  general  types  of  petroleum 
found  in  the  United  States:  (i)  Paraffine  petroleums,  (2)  semi- 
asphaltic  petroleums,  and  (3)  asphaltic  petroleums.  Paraffine 
petroleums  occur  mainly  in  the  eastern  part  of  the  United  States 
and  are  typified  by  the  Pennsylvania  oils.  The  semi-asphaltic 
variety  occurs  in  the  southern  and  middle  western  parts  of  the 
United  States.  Texas  is  one  of  the  main  sources  of  this  type. 
Asphaltic  petroleums  occur  in  the  western  part  of  the  United 
States,  particularly  in  California.  Petroleums,  if  of  semi-asphaltic 
or  asphaltic  character,  may  make  excellent  dust  palliatives  and 
road  binders  when  properly  treated. 

Petrolic  Ethers. — Very  light  volatile  naphthas  obtained  from 
petroleum. 

Pitches. — Semi-solid  or  solid  residues  produced  in  the  evapora- 
tion or  distillation  of  bitumens.  This  word  is  often  prefixed  by 
the  name  of  the  material  from  which  it  is  derived,  such  as  oil 
pitch,  coal-tar  pitch,  etc.  As  a  rule  the  term  pitch  is  confined  to 
the  harder  residuums,  most  of  which  are  too  hard  for  use  as 
road  binders  unless  fluxed  with  a  more  fluid  product. 

Pyrobitumens. — Mineral  organic  substances  which  are  but 
slightly  acted  upon  by  the  solvents  for  the  bitumens,  but  which, 
upon  being  subjected  to  destructive  distillation,  give  rise  to  the 
formation  of  bitumens.  Pyrobitumens  are  derived  in  nature  both 
from  bitumens  and  direct  metamorphosis  of  vegetable  matter. 
22 


338  e:nginee)ring  chemistry 

Among  the  former  class  may  be  mentioned  Albertite  and  Wurtzi- 
lite,  and  among  the  latter,  peat,  lignite,  and  bituminous  coal. 

Pyrogenetic. — Originating  from  the  action  of  heat.  Coal  tar 
is  thus  a  pyrogenetic  bitumen. 

Reduced  Petroleum  or  Reduced  Oils. — Residual  oils  produced 
from  crude  petroleum  by  the  removal  of  water  and  the  more  vola- 
tile oil  constituents,  without  chemically  altering  the  base  by 
cracking  or  other  means:  These  residues  are  often  made  by  dis- 
tilling the  crude  oil  under  reduced  pressure.  Such  products  are 
of  little  value  for  road  treatment  unless  formed  from  semi-asphal- 
tic  or  asphaltic  oils. 

Refined  Tar. — A  more  or  less  viscous  tar  which  is  produced 
by  evaporation  or  distillation  of  crude  tar  until  the  residue  is  of 
the  desired  consistency.  This  term  also  includes  blown  tars  and 
cut-back  products  produced  by  fluxing  tar  pitches  with  volatile 
or  non-volatile  distillates.  Refined  tars  are  of  value  both  as  dust 
palliatives  and  as  road  binders  in  the  treatment  of  macadam 
roads.  Their  binding  value  is  proportional  to  their  hardness 
within  certain  limits. 

Residual  Petroleums  or  Residual  Oils. — Heavy  viscous  resi- 
dues produced  by  the  evaporation  or  distillation  of  crude  petro- 
leum until  at  least  all  of  the  burning  oils  have  been  removed  and 
often  some  of  the  heavier  distillates  as  well.  Residual  oils  grade 
into  the  artificial  asphalts  and  oil  pitches  as  their  hardness  and 
viscosity  increase.  The  more  fluid  products,  if  obtained  from 
semi-asphaltic  or  asphaltic  petroleums,  serve  as  excellent  dust 
palliatives  and  semi-permanent  road  binders  for  the  surface 
treatment  of  roads.  The  more  viscous  products  are  often  suit- 
able for  the  surface  treatment  of  roads  if  applied  hot,  but  are 
seldom  of  value  in  road  construction  unless  produced  from  semi- 
asphaltic  or  asphaltic  oils. 

Residual  Tars. — Heavy  viscous  residues  produced  by  the 
evaporation  or  distillation  of  crude  tar  until  all  of  the  light  oils 
have  been  removed.  Residual  tars  grade  into  the  tar  pitches  as 
their  hardness  and  viscosity  increase.     If  they  do  not  contain  an 


ENGINEERING   CHEMISTRY  339 

excess  of  free  carbon,  they  are  as  a  rule  well  adapted  for  use  as 
binders  in  the  construction  of  macadam  roads. 

Rock  Asphalt  or  Bituminous  Rock. — A  term  applied  to  a  great 
variety  of  sandstones  and  limestones  more  or  less  impregnated 
with  maltha.  Deposits  of  such  material  are  widely  distributed 
over  the  United  States  and  vary  from  rock  which  is  friable  and 
wholly  dependent  upon  the  bitumen  to  hold  the  mineral  fragments 
together  to  solid  rock  having  merely  its  interstices  filled  with 
bitumen.  The  former  type  is  of  value  for  use  as  a  surface  binder 
in  the  construction  of  roads  when  the  maltha  shows  good  binding 
value  and  amounts  to  not  less  than  6  per  cent,  of  the  weight  of 
rock  asphalt. 

Semi-Asphaltic  Petroleums. — Semi-asphaltic  petroleums  or 
semi-asphaltic  oils  are  petroleums  containing  a  semi-asphaltic 
base,  i.  e.,  petroleums  whose  residues  produced  by  evaporation  or 
distillation,  while  composed  mainly  of  asphaltic  hydrocarbons, 
contain  also  a  certain  percentage  of  paraffine  wax.  They  thus, 
show  a  mixed  base.  If  their  percentage  of  heavy  paraffine  hydro- 
carbons is  not  excessive,  they  may  be  made  to  produce  good  dust 
preventives  and  road  binders. 

Short. — A  term  applied  to  bituminous  materials  which  are  non- 
ductile. 

Tar  Pitches. — Semi-solid  or  solid  residual  tars.  Owing  to  the 
general  brittleness  or  tar  pitches,  only  the  softer  varieties  are  of 
value  in  their  natural  condition  as  road  binders.  The  harder 
pitches  may,  however,  be  used  for  this  purpose  if  fluxed  to  suit- 
able consistency  with  heavy  or  dead  oil  distillates  of  tar. 

Tars. — Tars  are  artificial  or  pyrogenetic  bitumens  produced  as 
distillates  by  the  destructive  distillation  of  bitumens,  pyro-bitu- 
mens  and  other  organic  material. 

Water-Gas  Tars. — Mixtures  of  hydrocarbon  distillates,  mostly 
unsaturated  ring  compounds,  produced  by  cracking  oil  vapors  at 
high  temperatures  in  the  manufacture  of  carbureted  water  gas. 
Crude  water-gas  tar  is  a  thin,  oily  liquid  having  a  specific  gravity 
lying  usually  between  i  and  i.io.  As  a  rule  it  contains  a  consid- 
erable quantity  of  water  which  is,  however,  largely  removed  by 


340  engini:e:ring  chemistry 

mechanical  devices  before  the  tar  is  placed  upon  the  market.  This 
water  is  not  ammoniacal,  as  in  the  case  of  crude  coal  tars.  The 
composition  of  water-gas  tar  varies  with  the  character  of  the  oil 
which  is  carbureted  and  with  varying  conditions  attending  the 
carbureting  process.  It  always  shows  a  low  percentage  of  free 
carbon,  usually  less  than  2  per  cent.,  and  contains  little  or  no 
naphthalene  unless  previously  used  for  scrubbing  coal  gas.  Crude 
water-gas  tar  has  practically  no  binding  value  and  is  serviceable 
only  as  a  dust  palliative  in  the  surface  treatment  of  roads.  When 
reduced  to  proper  consistency  by  distillation,  however,  it  shows 
certain  desirable  properties  for  use  as  a  road  binder  both  for 
surface  treatment  and  macadam  construction.  Water-gas  tar 
may  also  be  used  in  the  preparation  of  road  binders  from  high- 
carbon  coal  tars.  When  this  is  done,  the  two  crude  tars  are  mixed 
in  such  proportion  that  when  distilled  to  the  desired  consistency 
the  mixture  will  contain  less  than  the  maximum  limit  of  free 
carbon  allowable. 

Specification  for  Sheet  Asphalt  Pavement.^ 

Sheet  Asphai,t. 

1.  On  the  concrete  foundation  shall  be  laid  the  asphalt  pavement 
proper,  consisting  of  a  binder  course  i  to  i^  inches  in  thickness  when 
compressed,  and  an  asphalt  wearing  surface  2  inches  when  compressed. 

2.  The  binder  course  shall  be  composed  of : 

(A)  Binder  stone. 

(B)  Sand. 

(C)  Asphaltic  cement. 

The  binder  stone  shall  be  composed  of  hard,  clean,  broken  stone,  all 
of  which  shall  pass  a  screen  having  circular  meshes  i  inch  in  diameter, 
arid  shall  be  graded  in  size  from  i  inch  down,  so  as  to  produce,  when 
mixed  with  the  proper  proportion  of  sand  and  of  asphaltic  cement,  the 
mesh  composition  as  herein  below  specified  for  the  binder  mixture.  If  the 
binder  stone  does  not  contain  the  required  amount  of  fine  material,  sound, 
clean,  broken  stone,  or  gravel,  passing  y^-'mch  diameter  mesh  screen,  and 
clean,  sharp  sand  passing  a  lo-inch  mesh  screen,  shall  be  added,  in  such 
proportions  as  will  supply  the  deficiency. 

The  binder  shall  be  composed  of  broken  stone  and  sand  as  above 
specified,  mixed  with  asphaltic  cement,  complying  with  the  requirements 
1  Jersey  City,  N.  J  ,  1914.  Portion  of  specification  relating  to  asphalt  constructions 
only. 


ENGINEERING   CHEMISTRY  34I 

hereinafter  described.  The  binder  stone -and  sand  shall  be  heated  in 
suitable  appliances,  not  higher  than  325°  F.,  and  shall  then  be  thoroughly 
mixed  by  machinery  with  asphaltic  cement  at  300°  F.,  in  such  proportion 
as  to  thoroughly  coat  the  stone  and  all  fine  particles  of  the  mineral 
aggregate,  and  produce  a  homogeneous  binder  mixture  having  life  and 
gloss  without  an  excess  of  asphaltic  cement. 

The  binder  mixture  as  laid  shall  comply  with  the  following  require- 
ments for  percentage  composition : 

Mineral  aggregate: 

Retained  by  i-inch  circular  mesh, per  cent,  of  total  mixture. 

Mineral  aggregate : 

Passing   i-inch   circular   mesh,    and    retained   by    J/2-inch   circular 
mesh,  35  to  65  per  cent,  of  total  mixture. 

Mineral  aggregate : 

Passing  lo-inch  mesh  sieve,  20  to  35  per  cent,  of  total  mixture. 

Bitumen : 

5  to  8  per  cent,  of  total  mixture. 

Penetration  of  asphaltic  cement : 
50  to  65. 

The  binder  mixture,  prepared  as  above  described,  shall  be  hauled  to 
the  work,  suitably  covered  with  canvas  while  in  transit  so  as  to  reach  the 
street  under  construction,  at  a  temperature  between  200°  and  325°  F. 
The  mixture  shall  then  be  promptly  spread  uniformly  upon  the  founda- 
tion, to  such  thickness  that  after  being  immediately  and  thoroughly  com- 
pacted by  ramming  and  rolling,  it  shall  have  an  average  thickness  of 
i^  inches,  and  its  upper  surface  shall  be  parallel  to  the  surface  of  the 
pavement  to  be  laid. 

Before  laying  the  binder  course,  the  surface  of  the  concrete  founda- 
tion shall  be  thoroughly  swept  and  cleaned,  and  all  dirt,  foreign  matter, 
and  loose  material  shall  be  removed. 

No  traffic,  except  such  as  may  be  required  in  depositing  the  surface, 
shall  be  allowed  on  the  binder  course. 

Any  part  of  the  binder  course  that  shows  lack  of  bond,  or  that  is  in 
any  way  defective  or  which  may  become  loose  or  broken  up  before  it  is 
covered  with  the  wearing  surface,  must  be  taken  up  and  removed  from 
the  street,  and  replaced  with  good  material,  properly  laid,  in  accordance 
with  these  specifications.  Binder  when  laid,  shall  be  followed  and  cov- 
ered with  wearing  surface  mixture  as  soon  as  practicable,  and  in  all  cases 
within  24  hours  after  laying,  in  order  to  effect  the  most  thorough  bond 
between  the  binder  and  wearing  surface.  The  binder  course  must  be 
kept  clean  and  as  free  from  traffic  as  is  possible  under  working  conditions. 

Generally  no  placing  of  binder  or  wearing  surface  will  be  permitted 
in  wet  weather,  but  work  of  this  character,  however,  may  continue  when 
overtaken   by   sudden   rain,   up   to  the   amount   which  may  be  in  transit 


342  ^NGINDEJRING   CHEMISTRY 

from  the  plant  at  the  time.  The  plant  shall,  however,  shut  down  under 
these  conditions,  and  no  additional  material  will  be  permitted  to  be  laid. 

No  binder  shall  be  laid  on  concrete  which  has  not  set  sufficiently  to 
withstand  properly  the  weight  of  the  roller. 

3.  The  asphalt  wearing  surface  shall  be  composed  of : 

(A)  Asphaltic  cement. 

(B)  Clean  sharp  sand, 

(C)  Finely  powdered  inorganic  dust. 

The  asphaltic  cement  shall  comply  with  the  requirements  hereinafter 
described. 

The  sand  shall  be  hard  grained,  moderately  sharp  and  clean.  As  used 
it  shall  be  so  graded  in  size  from  coarse  to  fine  as  to  produce  in  the 
finished  surface  mixture  the  mesh  composition  herein  named. 

The  inorganic  dust,  or  filter,  shall  be  finely  powdered  limestone,  Port- 
land cement,  or  other  satisfactory  inorganic  dust.  The  inorganic  dust  as 
used  must  be  thoroughly  dry,  and  of  such  a  degree  of  fineness  that  the 
whole  of  it  shall  pass  a  30-mesh  sieve,  and  not  less  than  66  per  cent,  shall 
pass  a  200-mesh  sieve. 

The  inorganic  dust  shall  be  free  from  loam,  clay,  or  earthly  material, 
and  no  dust  from  weather  rock  shall  be  used. 

The  wearing  surface  mixture  shall  be  composed  of  sand,  inorganic 
dust,  and  asphaltic  cement,  mixed  as  hereinafter  specified  in  definite  pro- 
portions by  weight,  depending  upon  their  character;  but  whatever  may  be 
the  character  of  the  composition  of  the  sand,  dust  and  asphaltic  cement 
used,  the  proportions  of  the  mixture  by  weight  shall  be  such  as  to  produce 
in  the  finished  pavement  mixture,  when  laid,  the  percentage  composition 
hereinafter  specified. 

The  wearing  surface  mixture  shall  not  exceed  the  maximum  per- 
centage, nor  contain  less  than  the  minimum  percentage  by  weight  of  the 
total  mixture  herein  specified  for  mesh  composition  of  the  mineral  aggre- 
gate and  percentage  of  bitumen,  as  follows : 

Retained  by  lo-mesh  sieve None 

Passing  lo-mesh  sieve 

Retained  by  40-mesh  sieve 10      to  35      per  cent. 

Passing  40-mesh  sieve 

Retained  by  8o-mesh  sieve 20      to  55      per  cent. 

Passing  8o-mesh  sieve 

Retained  by  200-mesh  sieve 10      to  30      per  cent. 

Passing  200-mesh  sieve 12      to  18      per  cent. 

Bitumen    9^  to  12Y2  per  cent. 

Penetration  of  asphaltic  cement 50      to  65 

The  term  "mineral  aggregate"  applied  to  the  asphalt  wearing  surface 
mixture  as  used  in  these  specifications,   shall   signify  the  entire  part  or 


EJNGINDKRING   CHEMISTRY  343 

percentage  thereof  insoluble  in  carbon  bisulphide,  including  collectively 
the  sand,  inorganic  dust,  and  such  native  mineral  matter  and  insoluble 
matter  from  the  refined  asphalt  as  may  be  contained  in  the  asphaltic 
cement. 

The  sand  and  the  asphaltic  cement  shall  be  heated  separately,  the  sand 
to  approximately  325°  F.  and  the  asphaltic  cement  to  approximately  300°  F. 
The  maximum  temperature  of  the  sand  as  delivered  at  the  mixing  box 
shall  in  no  case  exceed  350°  F.  The  cold,  inorganic  dust  shall  be  thor- 
oughly mixed  with  the  hot  sand  and  filler  at  the  required  temperature  and 
in  the  proper  proportions  until  a  homogeneous  mixture  is  produced,  in 
which  all  particles  are  thoroughly  coated  with  asphaltic  cement.  The 
sand,  dust  and  asphaltic  cement  comprising  the  charge  for  each  batch 
mixed  shall  be  proportioned  by  weight. 

The  surface  mixture  prepared  in  the  manner  above  described  shall 
be  brought  to  the  street  at  a  temperature  ranging  from  250°  to  325°  F., 
and  shall  be  suitably  covered  while  in  transit.  The  temperature  of  the 
mixture  within  the  above  limits  shall  be  regulated  according  to  the  tem- 
perature of  the  atmosphere  and  the  character  of  the  materials  employed. 
It  shall  then  be  deposited  roughly  in  place  by  means  of  hot  shovels,  and 
spread  uniformly  by  means  of  hot  iron  rakes,  in  such  manner  that,  after 
having  received  its  final  compression  by  rolling,  the  finished  pavement 
shall  .conform  to  the  established  grade  and  have  a  thickness  of  not  less 
than  2  inches.  Before  the  surface  mixture  is  placed,  all  contact  surfaces 
of  curbs,  manholes,  etc.,  shall  be  well  painted  with  hot  asphaltic  cement. 
After  raking,  the  surface  mixture  shall  at  once  be  compressed*  by  a  light 
steam  roller,  and  by  tamping  adjacent  to  the  curbs,  after  which  a  small 
amount  of  Portland  cement  shall  be  swept  over  it.  It  shall  thqn  be 
thoroughly  compressed  by  a  steam  roller  weighing  not  less  than  10  tons; 
the  rolling  being  continued  until  no  further  compression  is  obtained. 

A  space  of  12  inches  next  the  curb  shall  be  coated  with  hot  asphaltic 
cement,  and  the  same  ironed  into  the  pavement  with  hot  smoothing  irons. 

Definition  of  Asphai^t. 
The  term  "asphalt"  shall  signify  any  solid  natural  bitumen  or  the 
residue  from  the  distillation  of  an  asphaltic  petroleum,  or  natural  liquid 
bitumen  complying  with  the  requirements  hereinafter  set  forth.  Natural 
asphalt  may  be  either  in  a  state  of  purity,  or  in  admixture  with  native 
non-bituminous  matter.  The  word  "bitumen"  shall  signify  any  natural 
hydrocarbon  or  hydrocarbons  soluble  in  carbon  bisulphide. 

Penetration  Consistency. 
The  word  "penetration"  and  "consistency"  of  an  asphalt  or  bitumen, 
as  used  in  these  specifications,   shall   signify  "the  distance,   expressed  in 
hundredths  of  a  centimeter,  that  a  No.  2  needle  will  penetrate  it  at  'j'j"  F. 
in  5  seconds,  under  a  load  of  100  grams,"  unless  otherwise  specified. 


344  e:ngine:e:ring  chemistry 

AsPHALTic  Petroleum. 

A  petroleum  shall  be  designated  "asphaltic"  for  the  purposes  of  this 
specification,  if  the  bituminous  residue  therefrom  prepared  as  hereinafter 
described  fulfils  the  requirements  of  the  tests  set  forth  for  refined  asphalt. 

The  refined  asphalt  shall  be  obtained  as  follows : 

(a)  By  heating  solid  crude  natural  asphalt,  without  the  admixture  of 
any  other  material,  to  a  temperature  not  exceeding  400°  F.  until  all  the 
water  has  been  driven  off  and  the  product  is  homogeneous,  and  complies 
with  the  requirements  hereinafter  set  forth.  The  process  shall  be  con- 
tinued, if  necessary,  until  the  product  has  a  penetration  of  not  more 
than  30. 

(b)  By  the  distillation  of  asphaltic  petroleum  or  natural  liquid  bitu- 
men without  the  admixture  of  any  other  material,  at  a  temperature  not 
exceeding  700"  F.,  the  material  being  constantly  agitated  in  a  closed  tank 
during  said  distillation,  by  the  aid  of  steam  under  pressure,  or  other 
approved  methods  and  the  operation  continued  until  the  residual  asphalt 
has  a  penetration  of  not  more  than  60  nor  less  than  30.  The  average 
penetration  of  any  shipment,  within  the  above  limits  and  subject  to  the 
requirement  of  uniformity  of  shipments  hereinafter  specified  shall  be  as 
determined  by  the  engineer. 

No  Additions  to  Crude  Asphalt. 

Nothing  whatever  shall  be  added  to  the  crude  natural  material  at 
any  time,  either  before,  during  or  after  refining,  except  as  hereinafter 
provided.   ' 

The  preparation  and  refining  of  all  asphalts  for  use  under  these 
specifications  shall  be  subject  to  such  inspection  at  the  refineries  and 
paving  plants  as  the  engineer  may  direct,  and  said  preparation  and  refin- 
ing shall  in  all  cases  be  conducted  in  the  most  suitable  nad  approved 
manner. 

Recognized  Standard. 

Any  asphalt  proposed  to  be  used  or  furnished  under  this  contract 
shall  be  equal  in  quality  and  composition  to  the  recognized  standard  for 
its  particular  kind  or  type. 

Refined  Asphalts. 
All  refined  asphalts,  to  be  approved  for  use  under  these  specifications, 
must  comply  with  the  following  requirements: 

Penetration. 
It  shall  not  vary  more  than  15  units  in  penetration  from  maximum  to 
minimum. 

Ductility. 
Should  the  ductility  of  the  asphalt  of  any  part  of  any  shipment  fall 
below  75  centimeters,  it  will  be  required  that  the  ductility  of  the  asphalt 


Engine:ering  chemistry  345 

of  said  shipment  shall  not  vary  more  than  30  centimeters  in  ductility  from 
maximum  to  minimum. 

Not  less  than  98^  per  cent,  of  the  total  bitumen  of  all  refined  asphalts 
shall  be  soluble  in  carbon  tetrachloride. 

When  made  into  an  asphaltic  cement  by  the  use  of  such  materials 
and  methods  as  are  described  in  these  specifications,  they  must  produce 
an  asphaltic  cement  complying  with  all  the  requirements  hereinafter  set 
forth  for  asphaltic  cement. 

Volatilization. 
Under  the  volatilization  test  at  325°  F.  the  refined  asphalt  shall  not 
lose  more  than  3  per  cent,  of  the  bitumen  present,  nor  shall  the  penetra- 
tion after  such  heating  be  less  than  one-half  the  original  penetration. 
This  requirement  for  determining  the  "per  cent,  of  hardening"  shall  apply 
only  to  asphalts  having  a  penetration  of  10  or  more. 

Mixtures. 

No  mixtures  of  asphalts  either  at  the  refinery  or  at  the  paving  plant 
will  be  permitted  without  the  written  consent  of  the  engineer,  except  as 
provided  herein. 

The  use  of  asphalt  mixtures  will  be  permitted  only  provided  that : 

(a)  The  particular  kinds  of  asphalt  (each  of  which  shall  comply  with 
these  specifications)  and  the  proportions  thereof  are  approved  by  the 
engineer. 

(b)  The  mixtures  are  made  at  the  contractor's  plant  under  the  direct 
supervision  of  the  engineer. 

(c)  The  asphaltic  cement  resulting  from  such  mixture  complies  with 
all  the  requirements  for  asphaltic  cement  as  set  forth  under  section  on 
asphaltic  cement. 

Fluxes. 
The  fluxing  materials  shall  be  the  residuum  from  the  distillation  by 
the  aid  of  steam,  or  a  parafiine,  semi-asphaltic  or  asphaltic  petroleum. 
They  shall  be  of  such  character  that  they  will  combine  with  the  asphalt 
used  to  form  an  acceptable  and  approved  asphaltic  cement,  complying 
with  the  requirements  of  these  specifications.  In  each  case  the  proposed 
flux  shall  be  tested  with  the  asphalt  to  be  used  and  its  suitability  or  non- 
suitability  for  the  proposed  asphalt  will  be  determined  by  the  engineer. 

Residuums. 

(a)  Residuums  shall  contain  not  less  than  99  per  cent,  of  bitumen 
soluble  in  carbon  bisulphide  at  air  temperature,  of  which  bitumen  not  less 
than  98J/2  per  cent,  shall  be  soluble  in  carbon  tetrachloride. 

Penetration. 

(b)  Residuums  shall  have  a  penetration  greater  than  350  with  a  No.  2 
needle,  at  77°  F.,  under  50  grams  load  for  i  second. 


346  i:ngine:e:ring  chemistry 

Flash  Point. 

(c)  Residuums  shall  not  flash  below  350°  F.,  when  tested  in  a  New 
York  State  closed  oil  tester. 

Volatilization. 

(d)  Residuums  shall  not  lose  more  than  3  per  cent,  of  matter  by- 
volatilization  at  a  constant  temperature  of  325°  F.  for  5  hours.  The 
residue,  after  heating,  shall  be  homogeneous  and  shall  flow  at  77°  F. 

Specific  Gravity. 

(e)  Residuums  shall  have  a  specific  gravity  at  77°  F.,  of  not  less  than 
0.92  nor  more  than  i.oi. 

Paraffine  Residuums. 

Residuums  having  a  specific  gravity  of  not  less  than  0.92  nor  more 
than  0.94  at  77°  F.,  shall  be  designated  paraffine  residuums. 
Semi-Asphaltic  Residuums. 

Residuums  having  a  specific  gravity  of  not  less  than  0.94  nor  more 
than  0.98  at  77°  F.,  shall  be  designated  semi-asphaltic  residuums. 
Asphaltic  Residuums. 

Residuums  having  a  specific  gravity  of  not  less  than  0.98  nor  more 
than  I.OI  at  77°  F.  shall  be  designated  asphaltic  residuums. 
ASPHA1.TIC  Cement. 

If  the  refined  asphalt  has  the  penetration  required  for  asphaltic 
cement  hereinafter  specified,  it  may  be  used  without  flux,  and  said  refined 
asphalt  shall  be  considered  as  asphaltic  cement  and  shall  fulfil  all  the 
requirements  therefor.  If  the  refined  asphalt  is  not  of  the  required  pene- 
tration, an  asphaltic  cement  shall  be  prepared  from  refined  asphalt  and 
flux,  agreeing  in  all  respects  with  the  requirements  for  each  hereinbefore 
specified,  in  such  proportions  as  to  produce  an  asphaltic  cement  of  not 
less  than  40  nor  more  than  65  penetration,  when  used,  except  as  provided 
for  natural  asphalt  containing  mineral  matter. 

Penetration. 

The  asphaltic  cement  shall  have  a  penetration  within  the  limits  above 
specified,  but  the  penetration  shall  be  varied  within  these  limits  to  adapt 
it  to  the  character  of  the  particular  asphalt  used,  to  the  general  character 
of  the  mineral  aggregate  of  the  paving  mixture  and  to  the  character  of 
the  traffic  on  the  street.  The  penetration  of  the  asphaltic  cement  shall 
be  as  directed  by  the  engineer  in  writing  for  each  street  and  the  asphaltic 
cement  as  used  shall  not  vary  more  than  5  points  plus  or  minus  from  the 
penetration  directed. 

Mixing. 

The  refined  asphalt  and  flux  in  the  proper  proportions  to  produce  an 
asphaltic  cement  as  above  specified  shall  be  weighed  separately,  and  then 


EJNGINDERING   CHEMISTRY  347 

be  heated  and  melted  together  in  a  suitable  tank  and  thoroughly  agi- 
tated by  suitable  apparatus  until  completely  blended  into  a  homogeneous 
asphaltic  cement  to  the  satisfaction  of  the  engineer.  The  above  operation 
of  melting  and  heating  shall  be  conducted  at  a  temperature  of  not  less 
than  275°  F.  nor  more  than  350°  F.  During  use,  the  asphaltic  cement 
shall  be  maintained  at  approximately  325°  F. 

Heating. 

The  asphaltic  cement  must  not  be  heated  to  a  temperature  exceeding 
350°  F,  It  must  be  kept  uniform  in  composition  and  consistency,  and 
thoroughly  mixed  and  agitated  both  before  and  during  use.  Approved 
methods  of  agitation,  which  will  not  injure  the  cement,  must  be  used.  If 
kept  in  storage  in  a  molten  condition,  any  decrease  in  penetration,  or 
hardening,  shall  be  corrected  by  the  addition  and  thorough  incorporation 
of  a  proportionate  amount  of  flux  to  produce  the  desired  penetration 
before  using. 

The  refined  asphalt  and  flux  comprising  the  asphaltic  cement,  shall 
when  required,  be  weighed  separately  in  the  presence  of  the  engineer. 

The  asphaltic  cement  shall  comply  with  the  following  requirements : 

(a)  It  shall  be  completely  fluxed  and  thoroughly  homogeneous. 

Penetration. 

(b)  It  shall  have  the  penetration  between  40  and  65,  as  directed  by 
the  engineer  in  writing.  If  an  asphaltic  cement  contains  natural  mineral 
matter,  a  reduction  on  the  required  penetration  of  fine  points  shall  be 
made  for  each  10  per  cent,  of  such  natural  mineral  matter  present. 

Volatilisation. 

(c)  The  asphaltic  cement  shall  not  lose  more  than  3  per  cent,  of  the 
bitumen  present  by  volatilization  at  a  temperature  of  325°  F.,  nor  shall 
the  penetration  of  the  residue  after  such  heating  be  less  than  one-half  the 
original  penetration. 

Ductility. 

(d)  Either  the  asphaltic  cement  as  prepared  at  the  paving  plant  and 
as  used,  at  50  penetration,  or  the  purified  bitumen  obtained  therefrom  at 
50  penetration,  when  made  into  a  briquette  having  a  minimum  cross  sec- 
tion of  1  square  centimeter,  shall  have  a  ductility  at  77°  F.  of  not  less 
than  30  centimeters  at  the  time  of  rupture,  the  rate  of  elongation  being 
5  centimeters  per  minute. 

If  the  asphaltic  cement  as  used  complies  with  the  requirements  for 
ductility  no  test  of  the  purified  bitumen  for  ductility  will  be  required. 

If  the  consistency  of  the  asphaltic  cement  as  used  is  greater  or  less 
than  50  penetration,  or  of  the  purified  bitumen  therefrom,  above  men- 
tioned, is  greater  or  less  than  50  penetration,  the  above  requirement  for 
ductility  shall  be  as  follows : 


348  ENGINEERING    CHEMISTRY 

For  each  increase  of  5  units  in  penetration  of  the  asphaltic  cement 
as  used  (or  of  the  bitumen  therefrom)  above  50,  2  centimeters  shall  be 
added  to  the  requirement  for  ductility  at  50  penetration  as  above  estab- 
lished ;  and  for  each  decrease  of  5  units  in  penetration  of  the  asphaltic 
cement  as  used  (or  of  the  bitumen  therefrom)  below  50,  2  centimeters 
shall  be  subtracted  from  the  requirement  for  ductility  at  50  penetration 
as  above  established. 

Penetration  at  77°  and  100°  F. 

(e)  The  asphaltic  cement  when  at  a  penetration  of  50  at  77°  ¥., 
shall  not  be  so  susceptible  to  changes  in  temperature  that  the  difference 
between  its  penetration  at  100°  F,  and  at  32°  F.  shall  be  more  than  200; 
in  each  case,  the  penetration  test  being  made  with  a  No.  2  needle,  for  5 
seconds,  under  a  load  of  100  grams. 

If  the  asphaltic  cement  as  used,  has  a  penetration  greater  or  less  than 
50  at  77°  F.,  its  penetration  at  100°  F.  shall  not  exceed  four  times  its  pene- 
tration at  77°  F.,  the  conditions  of  time  and  load  being  as  above  established. 
Fluxed  Asphaltic  Cements. 

All  fluxed  asphaltic  cements  shall  be  prepared  at  the  contractor's 
paving  plant,  except  that,  in  case  satisfactory  reasons  are  given  for  the 
preparation  of  fluxed  asphaltic  cement  elsewhere,  the  same  shall  be  per- 
mitted only  with  the  consent  in  writing  of  the  engineer  and  under  his 
supervision. 

Bidders'  Samples. 

All  bidders  must  deposit  with  the  chief  engineer  at  his  oflice  in  the 
City  Hall,  Jersey  City,  N.  J.,  and  who  will  issue  a  receipt  for  same, 
samples  of  materials  intended  to  be  used,  5  days  before  the  date  bids  or 
proposals  are  advertised  to  be  received,  labeled  with  the  bidder's  name  and 
address  as  follows : 

(A)  A  sample  of  not  less  than  2  pounds  of  refined  asphalt,  together 

with  a  certificate  stating  the  name  of  the  asphalt  and  where 
same  was  mixed. 

(B)  A  sample  of  not  less  than  2  pounds  of  liquid  asphalt  flux,  if  any, 

accompanied  by  a  certificate  stating  where  same  is  mined,  and 
giving  its  fire  and  flash  tests  and  its  specific  gravity. 

(C)  A  sample  of  not  less  than  2  pounds  of  asphaltic  cement,  together 

with  a  certificate  stating  the  formula  used  in  its  composition, 
all  quantities  being  expressed  in  pounds. 

(D)  A  sample  of  not  less  than  2  pounds  of  crushed  stone  to  be  used 

in  the  binder  mixture. 

(E)  A  sample  of  not  less  than  2  pounds  of  sand  to  be  used  in  the 

asphalt  wearing  surface,  together  with  a  certificate  showing 
what  proportion  of  same  passes  a  200,  100,  80,  40  and  lo-mesh 
screen. 


ENGINEERING   CHEMISTRY 


349 


(F)  A  sample  of  not  less  than  2  pounds  of  powdered  inorganic  dust 
or  filler  to  be  used  in  the  asphalt  wearing  surface  mixture, 
together  with  a  certificate  stating  the  kind  of  material  from 
which  it  is  made  and  the  percentage  of  Avhich  passes  a 
200-mesh  screen. 


METHODS  FOR  TESTING  COAL  TAR  AND  REFINED  TARS, 
OILS  AND  PITCHES.* 


Determination  of  Water  in  Tar. 

The  apparatus  used  is  illustrated  in  Fig.  62. 


I 

■ 

■¥  i 

'1 

Fig.  62. 

Measure  50  cc.  of  coal  tar  naphtha  or  light  oil  (which  must  be 
tested  to  determine  that  it  is  free  from  water,  whenever  a  new 
supply  is  required)  in  a  250  cc.  measuring  cyhnder.  (No  ob- 
jection is  raised  to  measuring  the  tar  direct  into  the  still  or  in 
other  ways,  but  the  measurement  must  be  made  as  described  in 
case  of  dispute.)  Add  200  cc.  of  the  tar.  Transfer  contents  of 
cylinder  to  copper  still  and  wash  the  cylinder  with  50-75  cc.  more 
of  naphtha,  adding  the  washings  to  contents  of  the  still.  Attach 
lid  and   clamp,  using  a  paper  gasket  and  set  up  apparatus  as 

*  By  S.  R.  Church,  Chief  Chemist,  Barrett  Mfg.   Co.,  N.  Y.,  Jotir.  of  Indus,  and 
Eng.  Chemistry,  April,   191 1.     Position  only  given  here  by  consent  of  author. 


350  ENGINEERING   CHEMISTRY 

shown  in  Fig.  62.  Apply  heat  by  means  of  the  ring  burner  and 
distil  until  the  vapor  temperature,  as  indicated  by  the  ther- 
mometer (in  this  and  all  other  tests  care  must  be  used  to  have 
the  thermometer  set  exactly  as  shown  in  drawings)  has  reached 
205°  C.  (401°  F.).  The  distillate  is  collected  in  the  separatory 
funnel,  to  which  15-20  cc.  of  benzol  has  been  previously  added. 
This  effects  a  clean  separation  of  the  water  and  oil.  The  reading 
is  made  after  twirling  the  funnel  and  allowing  to  settle  for  a  few 
minutes.    The  percentage  is  figured  by  volume. 

Specific  Gravity. 

The  tar  is  dried  by  taking  300-400  cc.  in  the  apparatus  used 
for  water  determination  without  the  addition  of  naphtha.  The 
distillation  is  carried  to  170°  C.  (338°  F.)  vapor  temperature. 
Any  oil  which  has  distilled  over  is  separated  from  the  water  and 
returned  to  the  still  and  thoroughly  mixed  in  after  cooling.  Ap- 
paratus:  a  specific  gravity  bottle,  Hubbard  type  (special),  whose 
water  capacity  at  15.5°  C.  (60°  F.)  has  been  determined  by  ex- 
periment. Ten  grams  of  tar  are  introduced  at  a  temperature  of 
40-50°  into  the  weighing  bottle  and  the  weight  taken  after  cool- 
ing. Then  freshly  boiled  distilled  water  is  added  and  the  bottle 
kept  in  a  bath  at  15.5°  C.  (60°  F.)  until  no  further  contraction 
takes  place.  The  water  is  then  adjusted  to  the  mark  and  the 
bottle  removed  from  the  bath  and  weighed.  Weight  of  tar 
divided  by  the  weight  of  H^O  displaced  gives  the  specific  gravity. 
For  rough  determination,  as  of  wet  tar,  a  spindle  may  be  used  at 
any  convenient  temperature.  To  reduce  the  gravity  as  found  to 
15.5°  C,  0.000685  is  added  for  each  degree  C,  above  15.5°  C. 
(or  0.00038  for  each  degree  F.  above  60°  F.). 

Melting  Point. — Apparatus  shown  in  Fig.  63. 

I.  Pitches  from  43^-77°  C.  (iio°-i70°  F.).  A  clean-shaped 
^-inch  cube  of  the  pitch  to  be  formed  in  the  mold,  placed  on  the 
hook  of  No.  12  copper  wire,  and  suspended  in  the  600  cc.  beaker 
so  that  the  bottom  of  the  pitch  is  i  inch  above  the  bottom  of  the 
beaker.  (A  sheet  of  paper  placed  on  bottom  of  beaker  and  con- 
veniently weighted  will  prevent  pitch  from  sticking  to  the  beaker 
when  it  drops  off.)     The  pitch  to  remain  5  minutes  in  400  cc.  of 


Kngine:e:ring  chejmistry 


351 


water  at  a  temperature  of  15.5°  C.  before  heat  is  applied.  Heat 
to  be  applied  in  such  manner  that  the  temperature  of  the  water 
is  raised  5°  C.  (9°  F.)  each  minute.  The  temperature  recorded 
by  the  thermometer  at  the  instant  the  pitch  touches  bottom  of 
beaker  to  be  considered  the  melting  point. 


Fig.   63. — Melting  Point  Apparatus. 

2.  Below  43°  C.  (110°  F.)  the  same  method  can  be  used  except 
that  at  the  start  the  water  should  have  a  temperature  of  4°  C. 
(40°  F.) 

3.  For  pitches  from  yy^  C.  up  (170°  F.),  cottonseed  oil  should 
be  substituted  for  water;  otherwise  the  method  remains  the 
same.  With  these  harder  pitches,  it  may  be  necessary  to  heat  the 
pitch  in  order  to  form  a  cube.  Care  should  be  used  not  to  heat 
it  any  higher  than  is  necessary,  or  to  continue  heating  it  for  any 
length  of  time.  A  hot  knife  blade  will  often  assist  this  manipula- 
tion. 

Note. 
To  aid  the  removal  of  the  pitch  from  the  mold  it  may  be  greased  with 
a  very  thin  film  of  vaseline. 


352 


Engine:e:ring  chemistry 


Breaking  Point. 

A  small  piece  of  pitch  is  quickly  melted  directly  on  the  copper 
disk  on  the  steam  bath  to  a  layer  of  about  ^/g^  of  an  inch.  The 
disk  is  then  placed  in  the  porcelain  dish  and  well  covered  with 
water  of  about  ii°-i2°  C.  above  the  breaking  point  of  the  pitch. 


Fig.   64. — Breaking  Point   Apparatus. 

The  temperature  is  reduced  1°  per  minute  and  tested  from  time 
to  time  by  inserting  a  small,  thin  knife  blade  below  the  pitch  and 
turning  slightly  until  a  point  is  reached  at  which  the  pitch  snaps. 
This  is  taken  as  the  breaking  point.  The  copper  disc  should  be 
held  with  a  pair  of  tongs  and  not  with  the  fingers. 

Light  Oil  Distillation. 

One  hundred  cubic  centimeters  are  measured  in  a  cylinder  and 
transferred  to  the  200  cc.  Jena  glass  distilling  bulb  and  heated. 
The  distillate  is  collected  in  a  100  cc.  cylinder.  The  point  where 
the  first  drop  falls  from  the  end  of  the  condenser  is  noted  and 
thereafter  the  cubic  centimeter  distilled  noted  at  every  even  10°  C. 
continuing  until  95  per  cent,  of  the  oil  has  distilled.  Toward  the 
end,  the  condensing  water  must  be  heated  to  avoid  separation  of 
naphthalene. 

Redistillation. — The  extracted  oil  is  placed  in  the  Hempel  ap- 
paratus (Fig.  65,  apparatus  for  light  oil  distillation),  and  re- 
distilled, noting  the  cubic  centimeters  that  have  come  over  at  170° 
C.  and  200°  C,  at  which  latter  point  the  distillation  is  inter- 
rupted.^ 

1  The  fraction  — 170°   C.  shows  crude  benzol,  toluol  and  solvent;    170-200°   crude 
heavy  naphtha. 


ENGINEERING   CHEMISTRY 


353 


Naphthalene. — The  residue  above  200°  left  in  the  flask  in  D  is 
transferred  to  a  copper  beaker  and  cooled  to  15.5°  C.  for  15  min- 
utes and  the  dry  naphthalene  determined  as  under  creosote. 

CARBOI.IC     Ollv. 

A.  Specific  Gravity. — Apparatus — see  Fig.  65.  If  the  oil  is 
not  limpid  at  15.5°  C,  the  gravity  is  taken  at  a  higher  temperature 

I 


Fig.  65. — Light  Oil  Distillation.     No.  i — Distilling  Flask.     No.  2 — Condenser  (Special), 

No.  3 — Thermometer  (Standard).     No.  4 — ^Jena  Flask  (A.H.Thomas  1426,  200  cc). 

No.   5 — Hempel  Tube    (Special).      No.    6 — Graduated   Cylinder    (100   cc). 

and  0.0008  added  to  the  specific  gravity  for  every  degree  above 

15-5°. 

B.  Distillation. — Same  as  "Light  Oil." 

C.  Tar  Acids.—S^mt  as  'Xight  Oil." 

Benzoics. 
A.  Distillation. — Same  as  light  oil,  with  the  water  in  the  con- 
23 


354  ENGINEERING   CHEMISTRY 

denser  always  cold.^  With  C.  P.  benzol  or  toluol  readings  are 
taken  every  0.2°  C,  with  commercial  benzols  every  10°  C.  a 
reading  is  taken. 

B.  Gravity. — Hydrometer  at  15.5°  C. 

C.  Wash  Test. — Taken  only  on  water  white  grades. 

About  7  cc.  of  concentrated  HoSO^  and  21  cc.  of  the  benzol 
are  shaken  in  a  small  glass  stoppered  French  square  bottle  of 
30  cc.  capacity  and  the  coloration  of  the  acid  and  oil  noted. 

Creosote  Oils. 

A.  Standard  Creosoters  Distillation. — Method  is  given  in  Bidl. 
(55,  American  Railway  Engineering  and  Maintenance  of  Way 
Association. 

Before  beginning  the  distillation,  the  retort  should  be  care- 
fully weighed  and  exactly  100  grams  of  the  oil  placed  therein, 
the  same  being  weighed  in  the  retort.  The  thermometer  should 
be  inserted  in  the  retort  with  the  lower  end  of  the  bulb  ^  inch 
from  the  surface  of  the  oil,  and  the  condensing  tube  attached  to 
the  retort  by  a  tight  cork  joint.  The  distance  between  the  bulb 
of  the  thermometer  and  the  end  of  the  condensing  tube  should 
not  be  less  than  20  nor  more  than  24  inches,  and  during  the  prog- 
ress of  the  distillation  the  thermometer  must  remain  in  the  posi- 
tion originally  placed. 

The  distillates  should  be  collected  in  weighed  bottles  and  all 
fractions  determined  by  weight.  Reports  are  to  be  made  on  the 
following  fractions : 

0°  to  170°  C. 

170°  to  200°  C. 

200°  to  210°  C. 

210°  to  235°  C. 

235°  to  270°  C. 

270°  to  315°  C. 

315°  to  355°  C. 

For  practical  purposes  there  will  be  no  need  of  reporting  on 
all  of  these  fractions.  It  will  be  sufficient  to  report  on  the 
fractions  as  follows : 

^  Distillation  .continued  to  dryness  and  drying  point  recorded. 


DNGINEIE^RING   CHEJMISTRY  355 

Below  200°  C. 
200°  to  210°  C. 
210°  to  235°  C. 
235°  to  315°  C. 
Above    315°  C. 

Reports  are  to  be  made  on  individual  fractions.  In  making 
such  reports,  it  is  to  be  distinctly  understood  that  these  fractions 
do  not  necessarily  refer  to  individual  compounds.  In  other 
words,  the  fractions  between  210  and  235°  will  not  necessarily  be 
all  naphthalene,  but  will  probably  contain  a  number  of  other 
compounds. 

The  distillation  should  be  a  continuous  one  and  should  take 
about  45  minutes. 

When  any  measurable  quantity  of  water  is  present  in  the  oil, 
the  distillation  should  be  stopped,  the  oil  separated  from  the 
water,  and  returned  to  the  retort  when  the  distillation  should  be 
recommended,  and  the  previous  readings  discarded. 

In  obtaining  water- free  oil,  it  will  be  desirable  to  free  about 
300  to  600  cc.  of  the  oil  by  using  the  copper  tar  still  and  using 
100  grams  of  the  water-free  oil  for  the  final  distillation.  In  the 
final  report  as  to  fractions,  a  correction  must  be  made  for  the 
water  content,  so  that  the  report  may  be  made  on  the  basis  of  a 
dry  oil. 

Determination  of  Specific  Gravity  of  Oil. 

In  order  to  determine  the  specific  gravity  of  any  oil,  heat  the 
oil  in  a  water  bath  until  it  is  completely  liquid.  A  glass  stirring 
rod  dipped  into  the  liquid  should  show  no  solid  particle  on  the 
rod  when  the  same  is  withdrawn  from  the  oil.  When  completely 
liquid,  stir  thoroughly  and  fill  the  hydrometer  cylinder,  which 
has  previously  been  warmed.  Insert  a  specific  gravity  hydrom- 
eter, taking  care  that  the  hydrometer  does  not  touch  the  sides  or 
bottom  of  the  cylinder  when  the  reading  is  taken.  Take  the  tem- 
perature of  the  oil  and  make  a  correction  for  the  specific  gravity 
by  reducing  the  same  to  the  standard  temperature  of  15.5°  C.  or 
60°  F.  The  correct  gravity  is  obtained  by  multiplying  the  cor- 
rection figure  0.0008  by  the  number  of  degrees  C,  or  0.00044  by 


356  ENGINEE^RING   CHEMISTRY 

the  number  of  degrees  F.,  the  oil  is  found  to  be  above  15.5°  C, 
or  60°  F.  and  adding  the  product  to  the  observed  gravity. 

Notes. 

1.  Emphasis  is  laid  on  attention  to  details  and  importance  of  a  retort 
of  the  standard  size. 

2.  The  thermometer  used  must  be  of  standard  make,  gas-filled  and 
must  be  regularly  tested  for  accuracy. 

Creosote  Oil — Additional  Tests. 

A.  Drying  Oil. — Apparatus  as  in  drying  tar.  500  cc.  are  dis- 
tilled up  to  170°  C,  the  water  noted  and  the  oil  distilling  over 
returned  to  the  still  after  cooling. 

B.  Tar  Acids. — Apparatus  shown  in  Drawing  7.  100  cc.  of  oil 
measured  at  limpid  point,  placed  in  Jena  glass  bulb  and  distilled. 
The  distillation  is  continued  until  at  least  95  per  cent,  has  distilled 
off.  The  time  from  the  first  drop  to  the  end  should  occupy  about 
20  minutes.  The  condenser  tube  should  be  kept  warm  enough 
by  a  flame  during  the  operation  to  prevent  distillate  from 
solidifying.  Warm  the  contents  of  the  separatory  funnel  to 
60°  C.  in  water,  and  note  reading.  Add  50  cc.  of  a  10  per  cent, 
caustic  soda  solution.  Shake  well  and  allow  to  settle,  drawing  off 
the  clear  soda,  warming  again  to  60°,  and  noting  the  shrinkage. 
Add  30  cc.  of  soda  and  note  any  further  shrinkage.  Repeat,  if 
necessary,  until  no  further  shrinkage  is  noted.  Then  the  total 
shrinkage  is  the  per  cent,  of  tar  acids  in  the  heavy  oil. 

C.  Dry  Naphthalene. — The  extracted  oil  from  B.  is  placed  in 
a  copper  beaker  and  held  at  15.5°  C,  for  15  minutes.  The 
mass  is  filtered  on  a  perforated  funnel  in  a  suction  pump  and 
sucked  dry.  The  naphthalene  in  the  filter  is  then  pressed  between 
paper  in  a  letter  press  to  remove  all  oil  and  weighed.  The  per- 
centage is  figured  on  the  weights  of  original  oil  as  given  by  the 
gravity  at  the  limpid  point. 

D.  Limpid  Point. — About  5  cc.  taken  in  a  No.  4  or  No.  5  test 
tube  at  60°  C.  are  cooled,  stirring  with  a  thermometer  until  the 
first  crystals  begin  to  form.  This  point  is  taken  as  the  limpid 
point.    Cool  in  water  only,  if  necessary. 


E^NGINE^ERING   CHEMISTRY 


357 


Creosote  Oil — Special  Tests. 

A.  Distillation  as  in  Circular  112,  U.  S.  Department  of  Agri- 
culture, except  that  instead  of  the  Hempel  flask  as  described 
there,  a  500  cc.  Jena  flask  with  a  Hempel  tube  attached  is  used. 

B.  Gravities. — Apparatus.  This  is  standardized  with  the 
pipette  filled  with  water  at  60°  C.  Oil  at  60°  is  drawn  up  to  the 
mark  in  the  pipette,  replaced  in  the  outer  tube  and  weighed. 
This  can  be  used  only. when  i  or  2  cc.  of  oil  are  available. 

C.  Sulphonation  Test. — Apparatus,  see  Fig.  66.    Apparatus  for 


-©Ea-c^ 


Fig.  66. — Special  Heavy  Oil  Analysis.  No.   i — Separatory  Funnel  (Special).     No.  2^ 

Specific    Gravity   Tube    (Special).  No.    3 — Flask    (A.    H.    T.    14246-500    cc). 

No.    4 — Hempel    Tube.      No.  5 — Condenser.      No.    6 — Asbestos    Box. 

No.  7 — Asbestos  Pad.  No.  8 — Thermometer   (Stand). 

special  heavy  oil  analysis.  The  weighed  fraction  distilling  be- 
tween 305°-20°  C.  is  warmed  with  concentrated  H^SO^  (about 
4-5  volumes)  to  60°  C.  and  the  whole  transferred  to  the  separa- 
tory funnel.     The  flask  is  rinsed  three  times  with  more  concen- 


358  eNGINE:^RING   CHEMISTRY 

trated  tLSO^  and  the  rinsings  added  to  the  funnel.  Then  the 
funnel  is  stoppered  and  shaken,  cautiously  at  first;  afterwards 
vigorously,  for  about  15  minutes.  Then  let  settle  over  night. 
Then  the  acid  is  carefully  drawn  down  into  the  graduated  por- 
tion to  within  2  cc.  of  where  unsulphonated  residue  shows. 
Whether  any  is  visible  or  not  the  test  should  be  carried  further  as 
follows :  Add  about  20  cc.  water  and  let  settle  for  ^  hour. 
Then  draw  down  water  as  close  as  possible  without  drawing  out 
any  supernatent  oil  or  emulsion.  Then  add  10  cc.  strong  H2SO4 
and  let  settle  for  15  to  20  minutes.  Any  unsulphonated  residue 
will  now  settle  out  clear  and  give  a  distinct  reading.  If  under 
0.2  cc.  it  should  be  drawn  down  into  the  narrow  part  just  above 
the  stop-cock  where  it  can  be  estimated  to  o.oi  cc.  The  cubic 
centimeters  are  figured  as  percentages  on  the  weight  of  the  frac- 
tion taken. 

If  the  unsulphonated  oil  is  dark  in  color  it  should  be  treated 
with  an  excess  of  10  per  cent,  sodium  hydroxide  solution.  If  the 
oil  is  soluble  in  this  reagent,  the  test  is  regarded  as  negative. 

Specifications  for  Wood  Block  Pavement.* 

The  wood  to  be  used  shall  be  southern  Longleaf  pine  ("Pinus  Palus- 
tris,"  Miller  Syn;  "Pinus  Australis,"  Michaux)  according  to  the  nomen- 
clature used  by  Chas,  Mohr  and  Filibert  Roth  in  Bulletin  No.  13  (Revised 
Edition),  U.  S.  Dept.  of  Agriculture,  Division  of  Forestry,  1897;  and 
subject  to  inspection  in  the  stick  before  being  sawn  into  blocks.  The 
blocks  shall  be  cut  from  what  is  known  as  prime  timber  as  defined  by 
the  Interstate  Rules  of  1905,  namely:  All  timber  must  be  sound,  well 
manufactured,  saw-butted,  all  square  edge,  and  shall  be  free  from  the 
following  defects :  unsound,  loose  and  hollow  knots,  worm  holes  and  knot 
holes,  through  shakes  and  round  shakes  that  show  in  the  surface.  The 
blocks  shall  average  80  per  cent,  heart  wood ;  individual  blocks  may  con- 
tain not  over  50  per  cent,  sap  wood,  provided  the  timber  has  been  well 
cured  to  the  extent  that  sap  wood  is  "live"  (not  brittle)  and  the  sap 
wood  is  of  a  weight  not  less  than  42  pounds  per  cubic  foot.  Timber  shall 
be  properly  air  dried  so  that  blocks  as  cut  shall  not  weigh  more  than 
50  pounds  per  cubic  foot. 

The  annual  rings  in  the  timber  used  shall  average  not  less  than  8  per 
inch    measured    radially    from    the    heart    so    as    to    include    the    greatest 

*  Portions  relating  to  the  tests  for  coal  tar  used  in  the  specifications — Borough  of 
Manhattan,  N.  Y.,   19 14. 


Engine;e:ring  che:mistry  359 

number  of  rings  possible,  and  not  over  5  per  cent.  o£  the  stock  shall  show 
a  minimum  of  5  rings  in  any  single  inch  of  this  radius. 

Different  lots  of  timber  of  varying  weights  per  cubic  foot  due  to 
their  being  more  or  less  thoroughly  cured  or  dried,  shall  not  be  treated 
together  in  the  same  charge,  but  as  nearly  as  possible  timber  weighing 
from  38  to  42,  42  to  44,  44  to  46,  and  46  to  50  pounds  per  cubic  foot,  shall 
be  treated  in  separate  charges,  the  object  being  to  separate  the  blocks  for 
treatment  according  to  their  moisture  content. 

The  blocks  shall  be  not  less  than  5  inches  nor  more  than  9  inches  in 
length ;  and  4  inches  in  width.  The  depth  of  blocks  parallel  to  fiber  shall 
be  4]4  inches  with  an  allowable  variation  of  either  way  not  exceeding 
1/16  inch.  They  shall  not  vary  more  than  ^  inch  either  way  in  width. 
Adjacent  blocks  in  a  course  shall  not  vary  more  than  %  inch  in  width. 

The  oil  shall  be  sampled  before  treatment  is  begun  by  taking  a  drip 
sample  of  the  completely  liquefied  oil,  commencing  after  the  oil  has  started 
to  run  freely.  Where  this  cannot  be  done  samples  shall  be  taken  from 
various  depths  of  the  storage  tank. 

Samples  of  oil  shall  be  drawn  from  each  cylinder  charge  of  blocks  as 
treated,  and  tested  at  the  plant  as  deemed  advisable. 

Samples  taken  from  the  treating  tank  during  the  process  of  the  work 
shall  at  no  time  show  an  accumulation  of  more  than  2  per  cent,  of  sawdust 
and  dirt  or  other  foreign  matter,  or  more  than  3  per  cent,  of  water.  Due 
allowance  shall  be  made  for  such  accumulation  of  foreign  matter  by 
injecting  a  corresponding  quantity  of  oil  into  the  blocks. 

The  oil  with  which  the  blocks  are  treated  shall  be  at  least  75  per  cent, 
straight  coal  tar  product  and  shall  comply  with  the  following  requirements : 

(a)  The  specific  gravity  shall  not  be  less  than  1.08  and  not  more  than 
1. 12  at  38°  C. 

(b)  It  shall  contain  not  more  than  3  per  cent,  of  matter  insoluble  in 
hot  benzol  and  chloroform. 

(c)  When  subjected  to  distillation,  according  to  the  method  herein- 
after described  the  amount  of  distillate  based  on  water  free  oil  shall  be 
as  follows  : 

Up  to  200°  C,  not  more  than  1.5  per  cent. 

Up  to  235°  C,  not  more  than  20  per  cent. 

Up  to  315°  C,  not  less  than  20  per  cent  or  more  than  50  per  cent. 
The  fraction  distilling  between  235°  and  315°  C.  shall  have  a  gravity 
of  not  less  than  1.03  at  38°  C. 

One  hundred  grams  of  oil  shall  be  weighed  out  in  a  glass  retort 
preferably  made  of  Jena  glass,  having  a  capacity  to  bend  of  neck  of 
250  cc.  A  condensing  tube,  air  cooled,  is  attached  to  the  retort  of  such 
length  that  the  total  distance  from  the  tubular  to  the  end  of  the  con- 
densing tube  shall  be  approximately  60  centimeters.     The  tubular   shall 


360  i;ngine:e:ring  che:mistry 

be  fitted  with  a  cork  through  which  a  nitrogen  filled  thermometer,  about 
40  centimeters  in  length  graduated  in  single  degrees  and  registering  to 
400°  C,  shall  be  inserted  in  such  a  manner  that  the  bottom  of  the  bulb 
shall  be  J^  inch  above  the  liquid  at  the  time  distillation  commences  and 
during  the  progress  of  the  distillation  the  thermometer  must  remain  in 
the  position  originally  placed.  The  first  reading  on  the  emergent  stem 
of  the  thermometer  shall  be  not  less  than  the  50°  point  and  not  more 
than  the  80°  point  and  no  correction  is  to  be  made  for  the  emergent  stem. 
The  distillation  shall  be  made  in  a  place  free  from  draughts  and  the  bulb 
of  the  retort  protected  by  a  shield  of  heavy  asbestos  paper,  shall  be 
heated  by  the  direct  flame  of  an  adjustable  burner.  The  flame  shall  be 
regulated  in  such  a  manner  that  the  rate  of  distillation  shall  continuously 
be  not  slower  than  i  drop  per  second  and  not  faster  than  2  drops  per 
second.  The  distillates  shall  be  collected  in  weighed  Erlenmeyer  flasks. 
If  water  is  present  the  amount  shall  be  reported  separately,  all  results 
being  calculated  on  a  dry  oil  basis. 

For  each  shipment  of  blocks  made,  the  contractor  or  the  superintend- 
ent of  the  plant  of  manufacture  shall  furnish  the  engineer  a  certificate  to 
the  effect  that  only  oil  complying  with  the  foregoing  specifications,  and 
of  the  amount  specified  per  cubic  foot  has  been  used  in  the  treatment  of 
the  blocks  shipped ;  and  upon  completion  of  the  contract  shall  furnish  an 
affidavit  that  all  charges  of  blocks  manufactured  have  been  treated  with 
oil  in  compliance  with  the  above  specifications. 

The  treatment  shall  consist  of  two  operations : 

(a)   The  application  of  preliminary  steam  and  vacuum. 

{b)  The  injection  of  a  minimum  average  of  18  pounds  of  oil  into 
each  cubic  foot  of  timber.  In  addition  to  this  minimum  average  such 
additional  oil  shall  be  injected  into  the  timber,  depending  on  its  physical 
condition  as  shall  render  it  possible  for  the  treated  blocks  to  pass  a  5 
per  cent,  absorption  test  as  hereinafter  specified. 

Blocks  cut  from  timber  allowed  under  these  specifications  require 
longer  or  shorter  periods  of  treatment  in  proportion  to  its  being  more  or 
less  thoroughly  cured  as  to  its  sap  and  heart  content,  and  to  its  pitch 
content.  The  following  variations  in  treatment  are  required  for  charges 
of  which  the  averages  in  weight  per  cubic  foot  are  to  be  carefully  taken. 

(rt)  Timber — 38-42  pounds  per  cubic  foot. — lyive  steam  shall  be  ad- 
mitted into  the  cylinder  and  applied  to  the  blocks,  being  gradually  raised 
during  a  period  of  i  hour  to  15  pounds  boiler  gauge  pressure  and  about 
185°  F.,  which  pressure  shall  be  maintained  for  2  hours ;  then  a  vacuum 
of  not  less  than  22  inches  shall  be  applied  for  i^  hours,  the  temperature 
in  cylinder  maintained  at  not  less  than  155°  F. 

Oil   at   not   less   than    180°    F.   nor   more   than    190°    F.    shall   then   be 
admitted  and  the  pressure  gradually  raised  during  a  period  of  3  hours 


i;ngine:e;ring  che;mistry  361 

to  160  pounds,  or  until  an  average  of  18  pounds  of  oil  has  been  forced 
into  each  cubic  foot  of  blocks.  During  this  period  the  temperature  of 
the  oil  shall  not  be  allowed  to  fall  below  165°  F.  The  free  oil  shall  then 
be  expelled  from  the  cylinder, 

(b)  Timber — 42-44  pounds  per  cubic  foot. — Live  steam  shall  be  ad- 
mitted into  the  C3^1inder  and  applied  to  the  blocks,  being  gradually  raised 
during  a  period  of  i  hour  to  18  pounds  boiler  gauge  pressure  and  about 
190°  F.,  which  pressure  shall  be  maintained  for  a  period  of  3  hours ; 
then  a  vacuum  of  not  less  than  2^  inches  shall  be  applied  for  2  hours, 
the  temperature  in  cylinder  being  maintained  at  not  less  than  150°  F, 

Oil  at  not  less  than  180°  F.  nor  more  than  190°  F.  shall  then  be 
admitted  and  pressure  gradually  raised  during  a  period  of  3  hours  to 
165  pounds,  or  until  an  average  of  18  pounds  of  oil  has  been  forced  into 
each  cubic  foot  of  blocks.  During  this  period  the  temperature  of  the 
oil  shall  not  be  allowed  to  fall  below  165°  F.  The  free  oil  shall  then  be 
expelled  from  the  cylinder. 

(c)  Timber — 44-46  pounds  per  cubic  foot. — Live  steam  shall  be  ad- 
mitted into  the  cylinder  and  applied  to  the  blocks,  being  gradually  raised 
during  a  period  of  i  hour  to  20  pounds  boiler  gauge  pressure  and  about 
190°  F.,  which  pressure  shall  be  maintained  for  not  less  than  4  hours; 
then  a  vacuum  of  not  less  than  24  inches  shall  be  applied  for  2  hours, 
at  temperature  in  cylinder  being  maintained  at  not  less  than  140°  F. 

Oil  at  not  less  than  180°  F.,  nor  more  than  190°  F.  shall  then  be 
admitted  and  pressure  gradually  raised  during  a  period  of  3^/2  hours  to 
165  pounds  or  until  an  average  of  18  pounds  of  oil  has  been  forced  into 
each  cubic  foot  of  blocks.  During  this  period  the  temperature  of  the 
oil  shall  not  be  allowed  to  fall  below  165°  F.  The  free  oil  shall  then  be 
expelled  from  the  cylinder. 

(d)  Timber — 46-50  pounds  per  cubic  foot. — Live  steam  shall  be  ad- 
mitted into  the  cylinder  and  applied  to  the  blocks,  being  gradually  raised 
during  a  period  of  2  hours  to  25  pounds  boiler  gauge  pressure  and  220°  F., 
which  pressure  shall  be  maintained  for  not  less  than  5  hours ;  then  a 
vacuum  of  not  less  than  24  inches  shall  be  applied  for  2^  hours,  the 
temperature  in  cylinder  being  maintained  above  140°  F. 

Oil  at  not  less  than  180°  F.,  nor  more  than  190°  F,  shall  then  be 
admitted  and  pressure  gradually  raised  during  a  period  of  3>4  hours  to 
170  pounds  or  until  an  average  of  18  pounds  of  oil  have  been  forced  into 
each  cubic  foot  of  blocks.  During  this  period  the  temperature  of  the  oil 
shall  not  be  allowed  to  fall  below  165°  F,  The  free  oil  shall  then  be 
expelled  from  the  cylinder. 

In  applying  the  treatment  specified,  variations  and  changes  may  be 
made  from  time  to  time  in  duration  of  treatment  and  in  temperatures 
and  pressures  used,  to  suit  various  gravities  of  oil  and  different  varie- 
ties of  timber.     Such  may  be  specified  by  the  engineer,  but  shall  not  be 


362  ENGINEE^RING   CHEMISTRY 

continued  unless  their  use  is  clearly  warranted  by  an  improvement  in  the 
quality  of  the  blocks  manufactured.  This  shall  be  demonstrated  by  tests 
to  be  made  on  samples  of  each  charge  treated,  as  hereinafter  specified. 

Upon  the  completion  of  treatment,  charges  shall  be  allowed  to  remain 
in  cylinders  for  from  30  minutes  to  i  hour,  and  shall  then  be  withdrawn. 
The  blocks  shall  be  protected  from  the  sun  after  manufacture,  and  shall 
be  loaded  within  48  hours  thereafter  for  shipment. 

An  inspector  appointed  by  the  president  will  inspect  the  lumber  and 
other  materials  used  in  the  manufacture  and  treatment  of  the  blocks. 
Any  material  and  blocks  not  in  compliance  with  these  specifications  shall 
be  rejected.  The  inspection  shall  include  the  making  of  such  tests  upon 
materials  and  samples  of  treated  blocks  as  may  be  desired  by  the  engineer. 

The  manufacturer  shall  afford  the  engineer  every  facility  requested 
for  measuring  tanks,  cylinders,  cages,  etc.,  and  for  taking  and  analyzing 
samples  as  often  as  may  be  deemed  necessary,  including  the  use  of 
laboratory  and  such  apparatus  as  he  may  require. 

References. 

"Investigations  on  Coal  Tar  and  Some  of  Its  Products."  A.  R.  Warner 
and   W.   B.    Southerton,   Jour.    Gas  Lighting,   Feb.   27,    1912. 

"Methods  for  the  Examination  of  Bituminous  Road  Materials."  J^ulletin 
38,  Office  of  Public  Roads,  U.  S.  Dept.  Agr. 


THE  EXAMINATION  OF  LUBRICATING  OILS. 

The  generally  accepted  conditions  of  a  good  lubricant  are  as 
follows : 

1.  Body  enough  to  prevent  the  surfaces  to  which  it  is  applied 
from  coming  in  contact  with  each  other. 

2.  Freedom  from  corrosive  acids,  either  of  mineral,  animal, 
or  vegetable  origin. 

3.  As  fluid  as  possible,  consistent  with  "body." 

4.  A  minimum  coefficient  of  friction. 

5.  High  "flash"  and  "burning"  points. 

6.  Freedom  from  all  materials  liable  to  produce  oxidation  or 
"gumming,"  or  addition  of  "artificial  thickeners." 

7.  Must  not  be  easily  thinned  or  vaporized  by  heat  or  thick- 
ened by  cold. 

The  examinations  to  be  made  to  verify  the  above  are  both 
chemical  and  mechanical,  and  are  usually  arranged  in  the  follow- 
ing order : 

I.  Specific  gravity. 


ENGINEERING   CHEMISTRY 


363 


2.  Cold  test. 

3.  Viscosity. 

4.  Iodine  absorption. 

5.  Flash  and  fire  tests. 

6.  Acidity. 

7.  Maumene's  test. 

8.  Identification  of  the  oil,  whether  a  simple  mineral  oil,  animal 
oil,  vegetable  oil,  or  a  mixture. 

9.  Coefficient  of  friction. 

1.   Specific  Gravity. 

In  the  chemical  laboratory  the  hydrometers  used  are  generally 
marked  with  the  specific  gravity  direct.  In  the  oil  trade,  how- 
ever and  in  general  commercial  practice  the  Baume  hydrometer 
is  used,  and  the  following  precaution  is  necessary. 

If  the  oil  is  not  liquid  enough  to  flow  easily,  it  must  be  warmed 
until  so,  and  then  tested  with  the  hydrometer.  The  latter  should 
move  easily  and  freely  in  the  liquid.  As  all  specific  gravities  are 
comparable  at  60°  F.,  it  will  be  necessary  to  make  correction  for 
temperature;  if  the  temperature  of  the  oil  is  above  60°  F.,  the 
readings  of  the  hydrometer  are  too  large;  if  below  60°  F.,  the 
readings  are  too  small. 

To  convert  Baume  degrees  into  specific  gravity  the  following 
table  is  used : 


°Be. 

Sp.  gr. 

°B€. 

Sp.  gr. 

°B€. 

Sp.  gr. 

°B6. 

Sp.  gr. 

10 

1. 0000 

28 

0.8861 

46 

0.7955 

64 

0.7216 

II 

0.9929 

29 

0.8805 

47 

0.7910 

65 

0.7179 

12 

0.9859 

30 

0.8750 

48 

0.7865 

66 

0.7143 

13 

0.9790 

31 

0.8696 

49 

0.7821 

67 

0.7107 

14 

0.9722 

32 

0.8642 

50 

0.7778 

68 

0.7071 

15 

0.9655 

33 

0.8589 

51 

0.7735 

69 

0.7035 

16 

0.9589 

34 

0.8537 

52 

0.7692 

70 

0.7000 

17 

0.9524 

35 

0.8485 

53 

0.7650 

71 

0.6965 

18 

0.9459 

3b 

0.8434 

54 

0.7609 

72 

0,6931 

^9 

0.9396 

37 

0.8383 

55 

0.7568 

73 

0.6897 

20 

0.9333 

38 

0.8333 

56 

0.7527 

74 

21 

0.9272 

39 

0.8284 

57 

0.7487 

75 

0.6829 

22 

0.9211 

40 

0.8235 

58 

0.7447 

76 

0.6796 

23 

0.9150 

41 

0.8187 

59 

0.7407 

77 

0.6763 

24 

0.9091 

42 

0.8140 

60 

0.7368 

78 

0.6731 

25 

0.9032 

43 

0.8092 

61 

0.7330 

79 

0.6699 

26 

0.8970 

44 

0.8046 

62 

0.7292 

80 

0.6667 

27 

08917 

45 

0.8000 

63 

0.7254 

90 
100 

0.6363 
0.608b 

3^4 


ENGINEERING   CHEMISTRY 


For  liquids  lighter  than  water  sp.  gr.  = q^,  . 

130  4-     Be 

at  60°  F.  and  we  find  that  27.2  Baume  is  equal  to 
0.8906  specific  gravity.^ 

Fig.  67  represents  a  Tagliabue  hydrometer  for  oils ; 
it  contains  a  thermometer,  also  a  scale  to  make  the 
readings  at  60°  F.  Subtract  1°  Baume  for  every 
10°  F.  above  60°  F.,  and  add  1°  Baume  for  every 
10°  F.,  below  60°  F. 

Thus,  if  the  hydrometer,  when  placed  in  the  oil, 
reads  26°  Baume  and  the  temperature  of  the  oil  80°  F., 
the  correct  reading  will  be  24.7°  Baume  at  60°  F.  The 
specific  gravity  test  is  an  important  one;  by  it  an  ad- 
mixture of  certain  oils  with  mineral  oil  is  indicated. 
For  instance,  a  lubricating  oil  of  specific  gravity  0.915 
was  found  by  qualitative  analysis  to  be  composed  of 
mineral  oil  and  menhaden  oil.  Knowing  the  kinds 
of  oil  composing  the  mixture,  and  approximation  of  the 
per  cents,  would  be  obtained  as  follows : 

Minera  oil Specific  gravity  =  0.890  (B) 

Menhaden    oil Specific  gravity  ^^  0.927  (A) 

Specific  gravity  of  mixture =  0.915  ( M ) 

^  If  we  assume  the  standard  temperature  for  this  purpose  to  be 
15.5°  C.  the  gravity  of  any  oil  at  higher  or  lower  temperature  can  be 
calculated   from   the   following  formula: 

G  =  G'  +  K   (T  —  15.5°), 
in  which  G  is  the  specific  gravity  at  15.5°,  G'  the  specific  gravity  at  T, 
T  =  temp,  of  room,  and  K  a  factor  varying  with  the  different  oils  as 
follows: 

Factor  for  Calculating  Specific  Gravity  of  Oils.^ 

Correction  for   1°  C. 

Cod   liver   oil    0.000646 

Olive    oil     0.000629 

Rape    oil    ." 0.000620 

Lard    oil    0.000658 

Peanut    oil     0.000655 

Cottonseed    oil     0.000629 

Corn    oil    0.000630 

Sesame    oil    0.000624 

2  A.  E.  Ivcach,  "Food  Inspection  and  Analysis,"  p.  372,  gives  the 
formula  for  ordinary  use  as  G  =  G'  +  0.00064  (T  —  15.5°  C). 


m 


Fig.  67. 


ENGINEERING   CHEMISTRY 


365 


Let  A  --  M  =  C.     (0.927  —  0.915  =  0.012) 
M  —  B   =  D.      (0.915  —  0.980=0.025) 

^,  D  .         r    A    /  o  02S\ 

Then  ^    ,    .^  =  per  cent,  of  A  ( ^  ) , 

C  +  D       ^  V  0.037/ 


and 


— —  =  per  cent,  or  Bl I 

C  +  D        ^  V  0.037/ 

The  result  being 


Per  cent. 

Menhaden  oil   67.5 

Mineral  oil    32.5 

A  more  rapid  method  is  graphically  thus;  in  Fig.  68  let  the 


'-    ■ 1                            11 

1                           1     .yz'/L'  )H 

It.^ 

^-=^     1  ■ 

J920                                 i       -           

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:±±^-"f           i  4^ 

^10                           zh 

Zt--'             !            _     ^. 

^ju               __    __    --+---    -    - 

^           - 

1    "               ~          T~ 

^^                                 ,          <-.... 

1                                    ..... 

.QOd  -^                          -.--'■ 

J                       _                  - 

»^l                     .-K^ 

'1 

?! 

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.Hm^f                       .^=  6  7./  / 

_^-         jU.lLJZ         -^ 

^\ 

1 

?J 

1  _ 

t^ 

»88fl-ti_      ^              ^ 

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,&^ 

1 

^ 

"*" 

!   1 

1 

1 

►87(  it:                       i 

1 

■  ■'  ■ ■ 1  r  '■ 

;                          1 

1 

1 

1 

1 

.ftfiVl 

1           .             i    i 

I'll 

1 

'                  !    i 

^1                                                                           PptI- 

Cpi,*                     \                                      1       1 

.850      ±                                  __     ^iT 

^^"*       1  :                 111 

10 


zo 


30 


60 


TO 


«0 


lOQ 


40  •'i'^ 

Fig.   68. 

abscissas  represent  per  cents,  and  the  ordinates  the  specific  gravi- 
ties. From  the  point  indicated  (on  the  line  AB)  0.915  the  spe- 
cific gravity  of  the  mixture  the  per  cents,  are  read  on  abscissa 
line  67.5  for  A  and  32.5  per  cent,  for  B. 


366 


e:ngine:ering  chemistry 


Another  instrument  used  for  the  determination  of  the  specific 
gravity  of  oils  is  the  Westphal  balance,  as  improved  by  Williams.^ 

This  apparatus  (Fig.  69)  is  very  accurate  and  should  be  used 
as  a  check  determination  of  the  gravity  made  by  the  hydrometer. 


Fig.  69. 


Directions  for  Using  the  Williams-Westphal  Balance. 

To  Determine  the  Specific  Gravity  of  Liquids: — Hang  ther- 
mometer plummet  upon  hook  and  after  leveling  the  instrument, 
bring  beam  to  equilibrium  in  air  by  turning  the  adjusting  weight 
on  threaded  portion  of  the  beam.  It  is  desirable  to  verify  this 
adjustment  by  immersing  thermometer  plummet  in  distilled  water 
at  15°  C.  and  hanging  one  of  the  largest  horse-shoe  weights  upon 
the  hook;  this  should  exactly  restore  the  beam  to  equilibrium. 
Care  should  be  taken  that  the  thermometer  plummet  be  fully 
immersed  throughout  the  complete  swing  of  the  beam.  After 
wiping  plummet  it  is  immersed  in  the  solution  to  be  tested,  this 
having  been  brought  to  the  proper  temperature,  and  weights 
added,  beginning  with  largest  until  equilibrium  of  the  beam  is 

^  "For  Determination  of  the  Spec.  Grav.  of  L,iquids  and  Solids,  both  Soluble  and 
Insoluble  in  Water." 


Dngineering  chemistry 


367 


restored.  If  the  solution  is  heavier  than  water  one  of  the  largest 
weights  must  hang  on  the  hook  at  the  end  of  the  beam.  In  read- 
ing the  weights,  the  large  weight  at  the  end  of  the  beam  indi- 
cates one,  the  other  large  weight  indicates  tenths,  corresponding 
to  the  position  it  occupies  on  the  graduated  portion  of  the  beam, 
the  next  smaller  weight  indicates  hundredths,  the  next  smaller 
thousandths  and  the  smallest  ten-thousandths. 

To  Determine  the  Specific  Gravity  of  Solids  Insoluble  in 
Water: — The  plummet  is  first  wiped  dry,  the  pan  hanger  is 
attached  at  the  threaded  end  of  the  beam,  and  water  at  15°  C. 
is  added  until  the  lower  pan  is  immersed  throughout  the  complete 
swing  of  the  beam.  The  beam  is  now  adjusted  to  equilibrium  by 
turning  the  weight  on  threaded  portion  of  the  beam.     The  sub- 


iiiiiiii^ 


Fig.   70. 

Stance  is  now  placed  in  the  upper  pan  and  the  horse-shoe  weights 
added  as  above  until  equilibrium  is  restored.  This  gives  weight 
of  substance  in  air.  The  substance  if  in  the  form  of  a  fragment 
is  now  transferred  to  the  lower  pan,  if  in  the  form  of  a  powder 
the  upper  pan  with  its  contents  is  transferred  to  the  lower  posi- 


368  ENGINEERING    CHEMISTRY 

tion,  and  after  wiping  lower  pan  it  is  transferred  to  the  upper 
position.  Weights  are  now  added  until  equilibrium  is  restored, 
this  reading  giving  weights  of  substance  in  water.  Calculations  : — 

Weight  in  air  ^       .  _ 

^^^  .    , — : .  °    ^^  ■    , — -. ^Specific  gravity. 

Weight  in  air — Weight  m  water 

To  Determine  the  Specific  Gravity  of  a  Substance 
Acted  Upon  by  Water: — For  example,  Portland 
Cement.  Select  some  liquid  such  as  carbon  tetra- 
chloride, carbon  bisulphide  or  benzine,  which  has  no 
action  upon  the  substance.  Immerse  lower  pan  in  this 
li'quid,  and  after  adjusting  beam  to  equilibrium,  de- 
termine weight  in  air  and  weight  in  this  liquid  as 
above,  which  will  give  the  apparent  specific  gravity 
of  the  substance. 

To  Obtain  True  Specific  Gravity : — The  specific 
gravity  of  the  liquid  used  is  determined  with  thermom- 
eter plummet  and  the  apparent  specific  gravity  multi- 
plied by  specific  gravity  of  liquid  used,  gives  the  true 
specific  gravity  of  substance. 

If  oil  is  too  thick  at  ordinary  temperatures,  for  the 
determination  of  the  gravity,  it  should  be  heated  suffi- 
ciently and  the  modified  Westphal  balance  (Fig.  70) 
used. 

If  only  small  amounts  of  the  oil  are  obtainable  a 
small  picnometer,  or  an  Arseo-picnometer  of  Eichhorn 
can  be  used.  The  important  feature  of  this  instru- 
ment consists  in  a  small  glass  bulb  (attached  to  the 
spindle),  which  is  filled  with  the  liquid  whose  gravity 
is  to  be  taken.  Thus  instead  of  floating  the  entire  ap-| 
paratus  in  the  test  fluid,  only  a  very  small  quantity  of 
the  latter  is  required. 

The  glass  bulb  when  filled  with  the  test  fluid,  is 
closed  by  means  of  an  accurately  fitting  glass  stopper, 
and  the  instrument  is  then  placed  in  a  glass  cylinder 
filled  with  distilled  water  at   17.5°  C.    (Fig.  71).  pig" 

The  gravity  is  then  at  once  shown  on  the  divided  scale  in  upper 
portions  of  the  spindle. 


ENGINEERING    CHEMISTRY  369 

Tabi^e  of   Specific   Gravity  of  Oils  Used  with   Minerai, 
OiES  FOR  Lubricating  Purposes. 

Sp.  Gr. 

Sperm   oil 0.883 

Olive  oil 0.916 

Cotton-seed  oil  (white)    0.925 

Cotton-seed   oil    (brown)     0.930 

Castor  oil 0.960 

Mineral  oil    0.860  to  0.925 

Dolphin  oil    0.922 

Neatsfoot  oil 0.915 

Lard    oil    0.915 

Tallow  oil 0.903 

Menhaden  oil   ' 0.928 

Rape-seed  oil   0.916 

Resin  oil .0.980  to  1.05 

Blown  oils,  made  by  oxidation  of  rape-seed  oil,  cotton- 
seed oil,  etc 0.930  to  0.970 

Corn  oil   0.922 

2.    The  Cold  Test. 

The  degree  at  which  an  oil  becomes  semi-solid  and  refuses 
to  flow^  freely  is  considered  the  cold  test  and  is  performed  as 
follows : 

Fifty  cubic  centimeters  of  the  oil  are  transferred  to  a  narrow 
bottle  (capacity  lOO  cc),  stoppered  with  a  rubber  stopper,  through 
which  is  inserted  a  thermometer,  the  bulb  of  which  reaches  an 
inch  or  more  into  the  oil. 

The  bottle  is  placed  in  a  mixture  of  ice  and  salt,  or  other  freez- 
ing compound,  and  retained  there  until  the  oil  becomes  solid.  It 
is  then  removed  and  allowed  to  warm  until  the  contents  become 
somewhat  thinner  in  consistence.  The  bottle  is  inclined  from 
side  to  side  until  the  oil  begins  to  flow,  when  the  temperature  is 
taken. 

At  this  particular  temperature  the  oil  is  neither  at  its  normal 
fluidity,  nor  is  it  solid,  and  while  this  method  does  not  correctly 
indicate  the  exact  temperature  of  the  solidifying-point,  it  does 
show  the  point  at  which  the  oil  ceases  to  flow  readily,  the  im- 
portant one  to  the  oil  inspector. 
24 


370 


ENGINEJKRING    CHEMISTRY 


In  lubricating  oils,  to  be  used  in  railroad  practice,  this  cold  test 
is  a  vital  one,  and  receives  in  the  laboratories  of  the  different 
railroads  of  the  United  States  considerable  attention. 

A  mineral  lubricating  oil,  non-paraffine,  of  good  quality,  does 


P 


imiiiia 


Fig.   T2. 


not  show  any  material  difference  in  its  consistency  at  25°  C.  or 
10°  C,  but  a  radical  change  would  be  indicated  at  10°  C.  if  some 
of  the  animal  or  vegetable  oils  were  a  component. 

Fig.  72  represents  the  glass  apparatus  with  thermometer  ar- 


ENGINEEiRING   CHEMISTRY  37I 

ranged    for  the   cold  test,   and   is   surrounded   by   any   mixture 
capable  of  producing  the  required  degree  of  cold. 

The  following  determinations  of  the  cold  test,  made  in  my 
laboratory,  will  show  the  wide  range  in  this  regard  between  many 
of  the  oils,  used  in  lubrication: 


Degrees  F. 

Elain   oil    42:8 

Saponified    red    oil 41.0 

Prime  neatsfoot  oil 24.8 

White  neatsfoot  oil   — 

Pure  hoof  oil  42.8 

Prime    lard   oil    44.6 

No.  I  lard  oil  44.6 

XXX  lard  oil    37.4 

American  sod  oil    33.8 

English  sod  oil   75.0 

Tallow    oil    79.0 

Dog  fish  oil   19.0 

Right  whale  oil  (Pacific) 32.0 

Unbleached  bowhead  whale  oil   (Pacific) 19.0 

Bleached  whale  oil   (Pacific) 8.6 

Natural  sperm  oil   (Pacific) 32.0 

Bleached  sperm  oil  (Pacific) 24.8 

Herring  oil   (Pacific) 32.0 

Natural  winter  sperm  oil  (Atlantic) 30.2 

Bleached  winter  sperm  oil  (Atlantic) 24.8 

Natural  spring  sperm  oil   (Atlantic) 50.0 

Bleached  spring  sperm  oil  (Atlantic) 46.0 

Natural  winter  whale  oil   (Atlantic) 28.0 

Bleached  winter  whale  oil  (Atlantic) 23.0 

Natural  spring  whale  oil   (Atlantic) 41.0 

Bleached   spring  whale  oil    (Atlantic) 35.6 

Prime  crude  menhaden  oil 24.8 

Brown  strained  menhaden  oil 19.5 

Light  strained  menhaden  oil 19.5 

Natural  winter  menhaden  oil 16.O 

Bleached  winter  menhaden  oil 10.4 

Extra  bleached  winter  white  menhaden  oil 12.0 

Bank   oil    24.8 

Straits  oil 19.5 

Sea  elephant  oil 41.0 

Black  fish  oil 1 7.6 


3/2  ENGINEERING    CHEMISTRY 

Degrees  F. 

Resin  oil,  ist  run 37.4 

Resin  oil,  2d  run —  2.2 

Resin  oil,  3d  run —  4.0 

Castor  oil —  0.4 

Crude  cotton-seed  oil 19.4 

Prime  summer  yellow  cotton-seed  oil 23.0 

Off  quality  summer  yellow  cotton-seed  oil 21.0 

Prime  quality  winter  cotton-seed  oil 14.0 

Off  quality  winter  cotton-seed  oil 17.6 

Prime  quality  summer  white  cotton-seed  oil 26.6 

Off  quality  summer  white  cotton-seed  oil 17.6 

Prime  quality  winter  white  cotton-seed  oil 15.8 

Off  quality  winter  white  cotton-seed  oil 23.0 

No.  I  French  degras  oil 77.0 

No.  2  French  degras  oil 77.0 

English  degras  oil   64.4 

Olive  oil 37-4 

Oleo  oil   750 

3.   Viscosity. 

The  test  for  viscosity  or  ''body"  of  lubricating  oils  is  an  im- 
portant one. 

By  comparison  with  standards  an  oil  may  be  rated  as  to  its 
viscosity  thus  giving  one  of  the  values  required  for  a  lubricant. 

Engler's  apparatus — probably  the  first  used  for  this  purpose, 
is  made  of  metal  (copper)  and  its  general  plan  is  shown  in  Fig. 

73- 

This  instrument  is  the  standard  for  determining  the  viscosity 
of  oils  in  Germany,  and  is  also  a  standard  in  this  country. 
Recommended  by  U.  S.  Bureau  of  Standards  for  use  unless  an- 
other form  of  viscosimeter  is  called  for  in  the  specification. 

In  using  this  instrument  the  viscosity  of  an  oil  is  stated  in 
seconds  required  for  2CX)  cc.  of  the  oil  to  run  into  the  flask, 
240  cc.  of  the  oil  being  placed  in  the  viscosimeter.  Water  usually 
requiring  from  50  to  53  seconds  at  20°  C. 

Heat  can  be  applied  to  the  water  bath,  the  viscosity  being  de- 
termined at  any  temperature  required  up  to  100°  C.  Higher 
temperatures  to  360°  C.  can  be  secured  by  filling  the  outer  vessel 
with  paraffine  instead  of  water. 


ENGINEERING    CHEMISTRY 


373 


r 


Engler  recommends  that  all  viscosities  be  compared  with  water 
thus : 

If   water   requires   52   seconds    for   delivery   of   200   cc.   into 


Fig-    Tl- — Engler  Viscosimeter. 


the  receiving  flask,  and  the  same  amount  of  an  oil  under  examina- 


tion requires  130  seconds,  the  ratio  is  determined  by 


130 
52 


2.50» 


the  oil  thus  having  a  viscosity  of  2.5  times  that  of  water. 

"The  American   Society   for   Testing   Materials,"   Report   of 
Committee  D-2,  state  as  follows : 

In  case  it  is  desired  to  correct  for  specific  gravity  of  the  oil, 


374 


EJNGIN DURING   CHEMISTRY 


the  following  formula  which  gives  the  results  in  specific  viscosity 
can  be  used : 

time  of  efflux  of  oil 


Sp.  viscosity  =  sp.  grav.  X 


7-32. 


time  of  efflux  of  water 
If  it  is  necessary  to  use  a  quantity  of  oil  less  than  240  cc.  the 
following  quantities  can  be  employed  and  multiplied  by  the  cor- 
responding factor  :i 


Amount  of  oil  put  in,  cc. 

Amount  of  oil  run  out,  cc. 

Factor  to  change  to   200  cc.  run  out 
and  240  cc.  put  in 


120 
100 

1.65 


The  Saybolt  Standard  Universal  Viscosimeter. 

The  Saybolt  Standard  Universal  Viscosimeter  at  the  present 
time  is  used  as  the  standard  instrument  by  nearly  every  oil  manu- 
facturer, dealer  and  user. 

The  older  types  of  machines  are  adapted  to  just  one  or  two 
specific  temperatures  at  which  the  viscosity  of  the  oil  is  tested. 
Whereas  the  Saybolt  Standard  Universal  Viscosimeter  is  just 
what  the  name  implies  and  covers  the  following  wide  range: 

(i)   Cylinder,  valve  and  similar  oils  with  bath  at 212° 

and  oil  to  be  tested  at 210° 

(2)  Reduced  black  oils,  with  bath  and  oil  at 130° 

(3)  Neutral,  spindle,  paraffine  and  other  distilled  oils  at.   100° 

(4)  Or  4  at  70° 

It  will  be  seen  by  the  above  that  the  range  in  temperatures 
covers  practically  every  test  that  is  necessary  to  determine  the 
viscosity  value  of  an  oil. 

Hence  the  advantages  of  the  above  instruments  are : 

First.  That  it  saves  expense  due  to  the  fact  that  a  number  of 
instruments  are  combined  in  one. 

Second.     It  eliminates  varying  conditions. 

Third.  It  lessens  the  possibilities  of  error  due  to  the  use  of 
various  instruments. 

^  Gaus,   Chemische  Revue  der  Fette  und  H-arz-Industrie,  Vol.  VI,  p.  221. 


ENGINKE^RING   CHEjMISTRY 


375 


The  instrument  is  so  constructed  that  it  can  be  adapted  to  any 
laboratory.  It  is  equipped  with  an  electric  heating  device,  steam 
heating  device  and  gas  heating  device. 

The  bath  prescribed  is  a  paraffine  pale  engine  oil  with  a  flash 
of  about  350°  F.  to  400°  F.  to  be  used  for  viscosity  tests  at  all 
temperatures.  This  is  recommended  over  the  old  method  of  a 
salt  and  water  bath  because  oil  and  water  are  antagonistic.     If 


Fig.  74. — Saybolt  Standard  Universal  Viscosimeter. 

The  cut  shows  one-half  of  stand  jacket  and  of  bath  vessel  cut  away  to 

expose  inside  parts. 

for  instance,  a  few  drops  of  the  water  by  chance  became  mixed 
with  the  oil  upon  going  through  the  viscosity  tube  proper,  the  re- 
sult would  be  erroneous  to  a  very  marked  degree.  However, 
care  should  be  taken  not  to  allow  any  of  the  bath  to  become  mixed 
with  the  oil  to  be  tested. 

The  stirring  mechanism  is  very  convenient  for  the  tester  and 
enables  him  to  obtain  a  uniform  temperature  throughout  the  bath. 


376 


EiNXINEERING    CHEMISTRY 


Fig-   75- — Tagliabue's  Improved  Viscosimeter. 


DNGINE^ERING    CHEMISTRY  377 

Taking  viscosimetry  as  a  whole  the  Saybolt  Universal  Viscosi- 
meter  is  a  most  up-to-date,  accurate  and  convenient  instrument 
for  present  day  oil  testing. 

Tagliabue's  viscosimeter  (Fig.  75),  is  used  to  a  very  large 
extent  by  the  manufacturers  of  lubricating  oils  in  the  United 
States.    The  following  are  the  directions  for  its  use : 

To  Te;st  the)  Viscosity  of  O11.S  at  212°  Fahrenheit. 

Pour  water  into  boiler  through  opening  A,  after  unscrewing 
safety  valve  until  water  gauge  shows  that  the  boiler  is  full.  See 
that  stop-cock  B  is  open,  making  direct  connection  between  boiler 
and  upper  vessel  which  surrounds  the  receptacle  in  which  the  oil 
to  be  tested  is  placed:  Place  wire  holder  in  set  nut  C  and 
suspend  thermometer  so  that  the  bulb  of  thermometer  will  be 
about  y^  inch  from  the  bottom  of  oil  bath.  Then  after  care- 
fully straining  80  cc.  of  the  oil  to  be  tested,  which  of  course 
must  be  warmed  in  the  case  of  very  heavy  oils,  pour  same  into 
oil  bath.  Close  stop-cocks  D  and  E.  Screw  the  extension  F 
with  rubber  hose  attached  into  coupling  G  and  let  the  open  end 
of  hose  be  immersed  in  a  vessel  of  water  which  will  prevent  too 
large  a  loss  of  steam.  Place  lamp  or  Bunsen  burner  under  boiler; 
screw  steel  nipple  marked  212  on  to  stop-cock  H;  the  apparatus 
is  now  ready  to  use.  After  steam  is  generated  wait  until  ther- 
mometer in  oil  bath  shows  a  temperature  of  210^  or  211°;  then 
place  the  60  cc.  test  glass  under  stop-cock  H  so  that  the  stream 
of  oil  strikes  the  side  of  test  glass,  thereby  preventing  forming 
of  air  bubbles;  and  when  the  thermometer  indicates  its  highest 
point  open  the  faucet  H  simultaneously  with  the  starting  of  the 
watch  which  is  supplied  with  each  instrument. 

When  the  running  oil  reaches  the  60  cc.  mark  in  the  neck  of 
the  test  glass  the  watch  is  instantly  stopped  and  the  number  of 
seconds  noted.  Then  multiply  the  number  of  seconds  by  2, 
and  the  result  will  be  the  viscosity  of  the  oil.  For  example:  If 
60  cc.  of  oil  runs  through  in  loij^  seconds  the  viscosity  would 
be  203. 

It  is  best  to  repeat  the  test  until  sufficient  skill  is  attained  by 
practice  for  uniform  results. 


37^        •  ENGINEERING   CHEMISTRY 

It  is  also  necessary  to  keep  the  oil  well  stirred  before  making 
test  in  order  to  have  the  oil  at  a  uniform  temperature. 

To  Test  the  Viscosity  oe  O11.S  at  70°  Fahrenheit. 

Screw  the  steel  nipple  marked  70°  on  the  faucet  H,  close 
stop-cock  B,  thereby  closing  communication  between  boiler  and 
upper  vessel.  Also  close  stop-cock  E.  Fill  upper  vessel,  through 
opening  G,  with  water,  as  near  a  temperature  of  70°  as  possible, 
also  having  the  oil  to  be  tested,  at  the  same  temperature.  Hang 
the  thermometer  in  position,  and  after  stirring  the  oil  thoroughly, 
blow  through  the  rubber  tube  at  D,  thoroughly  mixing  the  water. 
Should  the  thermometer  show  a  lower  or  higher  temperature 
than  70°,  add  cold  or  warm  water  until  the  desired  temperature 
is  obtained.  Then  measure  carefully  90  cc.  of  oil  to  be  tested, 
placing  it  in  the  machine,  and  when  everything  is  ready,  open 
stop-cock,  and  start  watch  at  the  same  time,  and  allow  70  cc. 
to  pass  through  the  nipple,  and  as  soon  as  the  test  tube  is  filled 
to  the  70  cc.  marked  in  the  neck,  turn  off  the  stop-cock  and  stop 
watch  at  the  same  moment.  Should  it  take  the  70  cc.  96  seconds 
to  run  through  the  nipple,  multiply  this  by  2,  and  you  will 
have  the  viscosity  of  the  oil,  which  is  192  seconds.  (This  multi- 
plication by  2  is  to  render  readings  comparable  with  the  Saybolt 
viscosimeter.) 

"The  Doolittle  Torsion  Viscosimeter."  ^ 

used  in  the  railroad  laboratories  of  the  Philadelphia  and  Read- 
ing Railroad  Company,  is  briefly  described  as  follows : 

A  steel  wire  is  suspended  from  a  firm  support  and  fastened  to 
a  stem  which  passes  through  a  graduated  horizontal  disk,  thus 
measuring  accurately  the  torsion  of  the  wire.  The  disk  is  ad- 
justed so  that  the  index  point  reads  exactly  zero,  thus  showing 
that  there  is  no  torsion  in  the  wire  (Fig.  75a). 

A  cylinder  2  inches  long  by  i^  inches  in  diameter,  having  a 
slender  stem  by  which  to  suspend  it,  is  then  immersed  in  the  oil 
and  fastened  by  a  thumb-screw  on  the  lower  part  of  the  stem 
to  the  disk.    The  oil  is  surrounded  by  a  bath  of  water  or  paraf- 

ly.  Am.  Chem.  Soc,  15,  173. 


EJNGINKERING   CHEMISTRY 


379 


fine  wax  according  to  the  temperature  at  which  it  is  desired  to 
take  the  viscosity.  This  temperature  being  obtained  while  the 
disk  is  resting  on  its  supports,  the  wire  is  twisted  360°  by  means 
of  the  knob  at  the  top.  The  disk  being  released,  the  cylinder  ro- 
tates in  the  oil  by  virtue  of  the  torsion  of  the  wire. 


Fig.   75a. — Doolittle  Viscosimeter. 

The  action  now  observed  is  identical  with  that  of  the  pendulum. 

If  there  was  no  resistance  to  be  overcome,  the  disk  would  re- 
volve back  to  zero,  and  the  momentum  thus  acquired  would  carry 
it  to  360°  in  the  opposite  direction.  What  we  find  is  that  the  re- 
sistance of  the  oil  to  the  rotation  of  the  cylinder  causes  the  revolu- 


380  E^NGINEERING   CHE:mISTRY 

tion  to  fall  short  of  360°  and  that  the  greater  the  viscosity  of 
the  oil  the  greater  will  be  the  resistance  and  hence  the  retardation. 
We  find  this  retardation  to  be  a  very  delicate  measure  of  the  vis- 
cosity of  an  oil. 

There  are  a  number  of  ways  in  which  this  viscosity  may  be  ex- 
pressed, but  the  simplest  is  found  to  be  directly  in  the  number  of 
degrees  of  retardation  between  the  first  and  second  complete  arcs 
covered  by  the  pendulum.  For  example,  suppose  we  twist  the 
wire  360°  and  release  the  disk  so  that  rotation  begins.  In  order 
to  obtain  an  absolute  reading  to  start  from,  which  shall  be  inde- 
pendent of  any  slight  error  in  adjustment,  we  ignore  the  fact  that 
we  have  started  from  360°,  and  take  as  our  first  reading  the  end 
of  the  first  swing.     Suppose  our  readings  are  as  follows : 

Right,  350;  left,  338;  right,  328;  and  keeping  in  mind  the  vi- 
brations of  the  simple  pendulum  we  will  see  at  once  that  we  have 
read  two  complete  arcs  whose  difference  is  2.2'^  computed  as 
follows  : 

1st  arc,  Right  350°  +  Left      338°  =  688° 
2d  arc,  Left  338°       +  Right  328°  =  666° 

22°  retardation. 

In  order  to  secure  freedom  from  error  we  take  two  tests — one 
by  rotating  the  wire  to  the  right,  and  the  second  to  the  left.  If 
the  instrument  is  in  exact  adjustment  these  two  results  will  be 
the  same,  but  if  it  is  slightly  out,  the  mean  of  the  two  readings 
will  be  the  correct  reading. 

It  will  also  be  noticed  that  if  the  exact  retardation  due  to  the 
oil  alone  is  to  be  obtained  we  must  subtract  the  factor  for  the 
resistance  due  to  the  air  and  the  wire  itself.  These  are  readily 
obtained  by  allowing  the  cylinder  to  rotate  in  the  air  and  deter- 
mining the  retardation  exactly  as  we  have  done  above.  This  fac- 
tor remains  constant  for  each  instrument  and  is  simply  deducted 
from  all  results  obtained. 

The  Redwood^  Viscosimeter  is  on  the  general  principle  of  the 
Engler.  This  is  the  standard  viscosimeter  for  the  English  oil 
trade. 

V-  Soc.  Chem  Ind.,5,  158. 


ENGlNEBiRING   CHE:mISTRY 


381 


4.   Iodine  Absorption. 

The  determination  of  the  iodine  absorption  of  an  oil  is  prob- 
ably the  most  important  chemical  test  for  recognition  quan- 
titatively in  a  mixture  of  animal  or  vegetable  oils  with  mineral 
oils.  Introduced  by  Hubl^  it  has  since  maintained  this  position, 
though  other  chemists  have  introduced  the  bromine  absorption 
and  others  of  similar  character.  They  have  not  attained  the  uni- 
versal confidence  in  the  iodine  process. 

In  a  mixture  of  two  fatty  oils  with  a  mineral  oil,  the  best 
results  are  obtained  by  saponifying  and  separating  the  fatty 
acids  from  the  mineral  oil.  The  iodine  absorption  of  the  mixed 
fatty  acids  is  then  taken,  and  where  the  nature  of  them  has 
already  been  shown  by  color  tests,  etc.,  their  proportion  can  be 
indicated  by  the  following  formula : 

100  (I  —  n) 


Where  x  =  the  percentage  of  one  fat, 
3;  =  the  percentage  of  the  other, 
I  =;  iodine  degree  of  mixture, 
m  z=z  iodine  degree  of  fat  x, 
n  =  iodine  degree  of  fat,  y. 

The  method  is  as  follows : 

Twenty-five  grams  of  iodine  and  30  grams  of  mercuric  chlor- 
ide are  each  dissolved  in  500  cc.  of  95  per  cent,  alcohol,  uniting 
the  two  solutions,  and  allowing  to  stand  several  hours  before  use. 

It  is  then  standardized  by  tenth-normal  thiosulphate  sodium 
solution.  The  process  of  the  determination  of  the  iodine  absorp- 
tion of  an  oil  is  as  follows:  o.i  to  0.5  gram  of  the  fat  or  oil 
is  dissolved  in  10  cc.  of  purest  chloroform  in  a  well-stoppered 
flask,  and  20  cc.  of  the  iodine  solution  added.  The  amount  must 
be  finally  regulated  so  that  after  not  less  than  2  hours'  diges- 
tion the  mixture  possesses  a  dark  brown  tint ;  under  any  circum- 
stances it  is  necessary  to  have  a  considerable  excess  of  iodine  (at 
least  double  the  amount  absorbed  ought  to  be  present),  and  the 
digestion  should  be  from  6  to  8  hours.  Some  potassium  iodide 
solution  is  then  added,  and  the  whole  diluted  with   150  cc.  of 

^  Ding.  poly.  J.,  253,  281. 


382 


ENGINEERING   CHEMISTRY 


water,  and  tenth-normal  thiosulphate  solution  delivered  in  till 
the  color  is  nearly  discharged.  Starch  is  then  added,  and  the 
titration  finished  in  the  usual  way. 

If  more  than  two  fatty  oils  are  present  in  a  mixture  with  min- 
eral oil,  the  method  of  Warren^  can  be  used. 

The  following  determinations  of  the  iodine  absorption  made  in 
my  laboratory  are  indicative  of  the  variations  of  the  absorption 
by  the  different  oils : 


Prime  lard  oil 

No.  I  lard  oil 

XXX  lard  oil 

Oleo  oil • 

Prime  neatsfoot  oil 

Horse  oil 

Natural  bow-head  whale  oil 

Natural  winter  whale  oil 

Extra  bleached  winter  white  oil 

Bleached  spring  winter  white  oil 

Crude  sperm  oil 

Prime  quality  winter  white  cotton  seed  oil.  .  • 
Prime  quality  summer  white  cotton  seed  oil  • 
Prime  quality  winter  yellow  cotton  seed  oil.  • 
Prime  quality  summer  yellow  cotton  seed  oil 

Olive  oil 

Herring  oil 

Dog-fish  oil 

Porpoise  head  oil 

Resin  oil,  second  run 

Resin  oil,  third  run 

Rape  oil 

Corn  oil 


76.4 

77.2 

69.8 

69.9 

65.1 

65.6 

51.6 

51.6 

80. 1 

80.0 

82.3 

82.5 

130.5 

13'. I 

121. 1 

126.0 

124.9 

1 26. 1 

1 26. 1 

126.2 

82.3 

82.3 

116. 4 

114.9 

110.2 

110.6 

II5-9 

118.6 

104.0 

104.4 

81.0 

83.0 

122. 1 

123.8 

102.7 

104.7 

28.9 

29.1 

92.1 

93-4 

90.4 

92.2 

94.0 

106.8 

III.O 

115.0 

5.   Flash  and  Fire  Test. 

The  flash  point  is  the  degree  of  temperature  at  which  ignitable 
volatile  vapors  are  given  off  by  the  oil,  producing  a  flash  when 
brought  in  contact  with  a  small  flame.  The  fire  test  is  a  contin- 
uation of  the  flash  test  until  the  oil  permanently  ignites. 

The  method  used  by  the  chemists  of  the  Tide  Water  Oil  Co., 
N.  J.,  is  as  follows : 

The  Cleveland  cup  is  used.  Fig.  76.  A  bath  is  supplied  with 
this  cup  but  it  is  not  used  either  by  this  laboratory  or  the  labora- 
tories of  the  Standard  Oil  Co.     The  cup  is  filled  about  ^  inch 

1  Chem  News,  62,  215  :/.  Anal.  Appl.  Chem.,  5,  215. 


ENGINEE^RING   CHE^MISTRY 


383 


from    the    top,    and    a   thermometer    (Tagliabue's    bulb    immer- 
sion thermometer  showing  corrections   for  total   immersion)    is 


Fig.   76. — Apparatus  for  Determining  the   Flashing  and  Burning  Points  of 
Combustible  Liquids  Cleveland  Cup. 

suspended  so  that  the  bulb  is  entirely  immersed  in  the  oil  at  the 
center  of  the  cup  without  touching  the  bottom.     Heat  is  applied 


384  ENGINEERING   CHEMISTRY 

by  means  of  a  Bunsen  burner  so  that  the  temperature  is  raised 
at  the  rate  of  10°  F.  a  minute.  As  the  flashing  point  is  ap- 
proached, a  test  is  made  for  every  rise  of  2°  or  3°  by  slowly 
passing  the  test  flame  across  the  cup  horizontally  near  the  ther- 
mometer. The  test  should  be  made  in  a  place  free  from  draughts, 
and  the  test  flame  should  be  about  5  millimeters  long. 

Any  variation  in  these  conditions,  either  in  the  size  or  shape  of 
the  cup,  and  rate  of  heating,  or  the  method  of  testing,  may  lead  to 
an  appreciable  error.  It  has  been  our  experience,  that  a  test 
flame  longer  than  5  millimeters  gives  low  results,  and  one  smaller 
gives  high  results.  The  temperature  of  the  first  flash  is  recorded 
as  the  flashing  point  and  is  reported  in  even  50°  F.  i.  e. — 532°  F. 
would  be  read  530°  F.  and  533°  F.  would  read  535°  F. 

Feash  Point  (Ceosed  Cup). 

Foreign  countries  usually  test  high  flash  products  by  the 
Pensky-Martens  closed  cup.^  We  are,  therefore,  obliged  to  use 
this  cup  for  testing  export  lubricating  oils.  This  cup  is  prac- 
tically of  the  same  construction  as  the  Abel  cup  (which  is  used 
for  refined  oils).  The  rate  of  heating  is  the  same  10°  F.  per 
minute,  as  with  the  open-cup  method.  Care  must  be  exercised  in 
obtaining  samples  free  from  water  for  this  test,  as  the  presence  of 
aqueous  vapor  prevents  the  oil  from  flashing. 

The  heating  and  testing  is  continued  in  the  same  way  until,  on 
the  application  of  the  test  flame,  the  sample  takes  fire  which 
temperature  is  recorded  as  the  fire  test  or  burning  point. 

Pensky-Martens  Test. — Where  great  accuracy  is  required  the 
Pensky-Martens  tester  should  be  employed.  The  method  of 
operating  is  as  follows : 

Referring  to  Fig.  yy  B  is  the  oil  container,  which  is  placed  in 
a  metal  heating  vessel  H,  provided  with  a  mantle  L  in  order  to 
protect  the  heating  vessel  from  loss  of  heat  by  radiation.  The 
oil  cup  B  is  closed  by  a  tightly-fitting  lid  (show^n  in  plan). 
Through  the  center  of  the  lid  passes  a  shaft  carrying  the  stir- 
ring arrangement,  which  is  worked  by  means  of  the  handle  /. 
In  another  opening  of  the  cover  is  fixed  a  thermometer.     The 

^  See  Fig.  77. 


r 


E^NGINKERING    CHEMISTRY 


385 


lid  is  perforated  with  several  orifices,  which  are  left  open  or 
covered,  as  the  case  may  be,  by  a  sliding  cover.  This  can  be 
rotated  by  turning  the  vertical  spindle  by  means  of  the  milled 
head  G.     By  turning  G,  an  opening  of  the  slide  can  be  made  to 


Fig-   77- — Pensky-Martens  Tester. 

coincide  with  an  orifice  in  the  cover,  and  simultaneously  a  very 
small  flame,  burning  at  the  movable  jet  B,  is  tilted  on  to  the 
surface  of  the  oil. 

The  test  is  performed  by  filling  the  oil  into  the  oil  cup  up  to 
a  certain  mark,  fixing  the  cover,  and  heating  the  oil  somewhat 
rapidly  at  first,  until  its  temperature  is  about  30°  C.  below  the 
25 


386  ENGINEERING   CHEMISTRY 

expected  flash-point.  The  temperature  is  then  allowed  to  rise 
very  slowly  by  making  suitable  use  of  the  wire  gauze  shown  in 
the  figures,  so  that  the  rise  of  temperature  within  ^  minute  does 
not  exceed  about  2°  C.  From  time  to  time  the  milled  head  G  is 
turned  and  the  flame  tilted  into  the  oil  cup.  The  temperature  at 
which  a  slight  explosion  is  produced  is  noted  as  the  flash  point  of 
the  oil. 

6.   Acidity. 

Acidity  in  oils  is  generally  due  to  a  partial  decomposition  of 
the  oil  with  liberation  of  fatty  acids.  These  latter  act  as  corro- 
sive agents,  attacking  the  metal  bearings  of  machinery,  forming 
"metallic  soaps"  and  producing  gumming  and  thickening  of  the 
lubricant. 

Properly  refined  mineral  oils  are  free  from  acidity,  but  nearly 
all  animal  and  vegetable  oils  possess  it  more  or  less. 

In  palm  oil,  for  instance,  the  free  fatty  acids  vary  from  12  to 
80  per  cent.  In  89  samples  of  olive  oil  intended  for  lubricating 
purposes,  D.  Archbutt^  found  from  2.2  to  25.1  per  cent,  of  free 
acid  (oleic,  the  mean  being  8.05  per  cent. 

The  action  of  free  acid  on  journals,  bearing,  etc.,  as  a  corro- 
sive agent,  has  led  many  engineers  to  include  a  test  of  free  acid 
direct  upon  copper  and  iron. 

This  is  done  by  suspending  weighed  pieces  of  sheet  copper  and 
iron  in  the  different  oils,  for  a  number  of  days,  heating  if  neces- 
sary and  determining  the  amount  of  metal  dissolved  by  the  oils. 

While  this  test  may  be  indicative  of  the  acidity  of  oils,  no  ratio 
exists  between  the  action  upon  gopper  and  iron  or  even  between 
the  oils  themselves  in  this  respect,  owing  to  the  varying  quantity 
of  acid  in  the  same  oils. 

Oleic  acid  cannot  be  present  as  a  constituent  of  a  pure  mineral 
oil ;  still  the  acid  test  should  be  made,  since  poorly  refined  mineral 
oils  are  liable  to  contain  small  amounts  of  sulphuric  apid  left  in 
the  process  of  refining.  The  sulphuric  acid  is  easily  indicated  by 
warming  some  of  the  oil  with  distilled  water,  adding  a  few  drops 

1  Analyst,  9,  171. 


Engineering  chemistry  387 

of  hydrochloric  acid   (dilute)   and  solution  of  barium  chloride. 
A  white  cloud  of  precipitate  shows  the  presence  of  sulphuric  acid. 
The  following  is  the  method  for  determining  the  acidity  of  oils 
as  used  in  many  of  the  railroad  laboratories : 

Materials  Required. 
5^2  dozen  4-ounce  sample  bottles. 
3  10  cc,  pipettes,  or  i£  desired  a  balance  weighing  milligrams. 

1  30  cc.  burette,  graduated  to  tenths  (burette  holder  if  desired),  with 

pinch-cock  and  delivery  tube. 

2  ounces  alcoholic  solution  of  turmeric. 

2  quarts  95  per  cent,  alcohol  to  which  ^  ounce  dry  carbonate  of 
soda  has  been  added  and  thoroughly  shaken. 

I  quart  caustic  potash  solution,  of  such  strength  that  31^2  cc.  exactly 
neutralize  5  cc.  of  a  mixture  of  sulphuric  acid  and  water,  which 
contains  49  milligrams  H2SO4  per  cubic  centimeter. 

Operation. 

Take  about  2  ounces  of  the  clear  alcohol  and  add  a  few 
drops  of  the  turmeric  solution,  which  should  color  the  alcohol 
red,  warm  to  about  150°  F.,  then  add  8.9  grams  of  the  oil  to 
be  tested  and  shake  thoroughly.  The  color  of  the  solution 
changes  to  yellow.  Fill  the  burette  to  the  top  of  the  graduation 
with  caustic  potash  solution,  and  then  run  this 'solution  from  the 
burette  into  the  bottle,  a  little  at  a  time,  with  frequent  shaking, 
until  the  color  changes  to  red  again.  The  red  color  must  remain 
after  the  last  thorough  shaking.  Now  read  off  how  many  cubic 
centimeters  and  tenths  of  the  caustic  potash  solution  have  been 
used,  and  this  figure  shows  whether  the  material  meets  specifica- 
tions or  not. 

To  determine  the  free  acid  in  tallow,  everything  is  done  ex- 
actly as  above  described,  except  that  the  tallow  is  melted  before  it 
is  added  to  the  alcohol. 

Ten  cubic  centimeters  of  extra  lard  oil,  at  ordinary  tempera- 
tures, and  the  same  amount  of  melted  tallow  at  100°  F.,  weigh 
almost  exactly  8.9  grams.  In  ordinary  work,  therefore,  it  will 
probably  not  be  necessary  to  weigh  the  oil  or  tallow.  Measure- 
ment with  a  10  cc.  pipette,  will  usually  be  sufficiently  accurate, 
provided  the  pipette  is  warmed  to  about  250°  F.,  and  allowed  to 


388  i:nginee:ring  chemistry 

drain,  the  last  drops  being  blown  out.     In  case  of  dispute,  how- 
ever, the  balance  must  be  used.     (P.  R.  R.  method.) 

Lard  and  tallow  are  very  liable  to  have  considerable  amounts 
of  free  acid.  The  specification  of  purchase,  therefore,  generally 
states   the   limits   of    free   acid   permitted. 

Freje  Acid  Test. 

(Amer.  Society  for  Testing  Materials. ) 

"About  10  grams  of  the  oil  are  weighed  into  a  200  cc.  Jena 

Erlenmeyer  flask,  60  cc.  of  neutral  alcohol  added,  the  mixture 

warmed  to  about  60°  C.  and  titrated  with  N/6  KOH,  using 

phenolphthalein,  the  flask  being  frequently  and  thoroughly  shaken. 

"The  result  in  the  case  of  a  mineral  oil  is  usually  reported  in 
percentage  of  sulphuric  anhydride  (SO3)  :  with  an  organic  oil, 
in  percentage  of  oleic  acid. 

"It  is  suggested  that  it  be  reported,  as  with  the  saponification 
value,  as  the  number  of  milligrams  of  KOH  necessary  to  neu- 
tralize the  acidity  of  i  gram  of  oil." 

Specifications  for  Lard  Oil. 

Must  be  of  the  best  quality  and  made  from  fresh  lard ;  to  be  pur- 
chased and  inspected  by  weight;  the  number  of  pounds  per  gallon  to  be 
determined  b}^  the  specific  gravity  of  the  oil  at  60°  F.  multiplied  by  8.33 
pounds,  the  weight  of  a  gallon  (231  cubic  inches)  of  distilled  water  at  the 
same  temperature. 

Oil  will  not  be  accepted  which — 

I,  Contains  admixture  of  any  other  oil. 
II.  Contains  more  acidity  than  the  equivalent  of  2  per  cent,  of 
oleic  acid. 

III.  Shows  a  cold  test  above  42°  F. 

IV.  Shows    coloration    when    tested    with    nitrate    of    silver,    as 

described  below. 
V.  A  half  pint  of  the  oil  placed  in  an  ordinary  hand  lamp  with- 
out a  chimney  must  burn  with  a  clear,  bright  flame  until 
90  per  cent,  of  the  oil  has  been  consumed ;  the  lamp  to  be 
placed  where  it  will  not  be  affected  by  draft  or  air  cur- 
rents and  the  wick  not  to  be  touched  during  the  trial. 
I.  Test  of  Lard  Oil. — The  cold  test  of  oil  is  determined  as  follows: 
A  couple  of  ounces  of  oil  is  put  in  a  4-ounce  sample  bottle  and  a  ther- 


Engine;ertng  chemistry  389 

mometer  placed  in  it.  The  oil  is  then  frozen,  a  freezing  mixture  of  ice 
and  salt  being  used  if  necessary.  When  the  oil  has  become  hard,  the 
bottle  is  removed  from  the  freezing  mixture  and  the  frozen  oil  allowed 
to  soften,  being  stirred  and  thoroughly  mixed  at  the  same  time  by  means 
of  the  thermometer  until  the  mass  will  run  from  one  end  of  the  bottle  to 
the  other.  The  reading  of  the  thermometer,  when  this  is  the  case,  is 
regarded  as  the  cold  test  of  the  oil. 

2.  The  nitrate  of  silver  test  is  as  follows :  Have  ready  a  solution  of 
nitrate  of  silver  in  alcohol  and  ether,  made  on  the  following  formula: 

Nitrate  of  silver i  gram 

Alcohol    200  grams 

Ether   40  grams 

After  the  ingredients  are  mixed  and  dissolved  allow  the  solution  to 
stand  in  the  sun  or  in  diffused  light  until  it  has  become  perfectly  clear. 
It  is  then  ready  for  use,  and  should  be  kept  in  a  dim  place  and  tightly 
corked. 

Into  a  50  cc.  test  tube  put  10  cc.  of  the  oil  to  be  tested  (which  should 
have  been  previously  filtered  through  washed  filter  paper)  and  5  cc.  of 
the  above  solution ;  shake  thoroughly  and  heat  in  a  vessel  of  boiling  water 
15  minutes,  with  occasional  shaking.  Satisfactory  oil  shows  no  change 
of  color  under  this  test. 

3.  For  the  burning  test  an  ordinary  tin  hand  lamp  to  conform  to  the 
following  description  will  be  used : 

Diameter  of  lamp  at  base,  s%  inches ;  height  of  cylindrical  portion, 
2j4  inches ;  height  of  top  of  burner  from  bottom  of  lamp,  2%  inches. 

The  burner  will  consist  of  two  conical  tubes  placed  side  by  side,  each 
iJ/2  inches  in  length,  15/64  inch  inside  diameter  at  top,  and  11/32  inch 
inside  diameter  at  bottom.  The  wick  will  consist  of  a  sufficient  number 
of  threads  of  ordinary  cotton  lampwicking  in  each  tube  to  make  a  prop- 
erly fitting  wick  for  lard  oil. 

Inspection  and  Delivery. 

I.  Before  acceptance  the  oil  will  be  inspected.  Samples  of  each  lot 
will  be  taken  at  random,  the  samples  well  mixed  together  in  a  clean 
vessel,  and  the  sample  for  test  taken  from  this  mixture.  Should  the 
mixture  be  found  to  contain  any  impurities  or  adulterations,  the  whole 
delivery  of  oil  it  represents  will  be  rejected. 

Maumene's  Test. 

The   rise   of   temperature   produced   when   sulphuric   acid   is 
brought  in  contact  with  certain  oils  was   first  investigated  by 


390  EJNGIN^KRING   CHEJMISTRY 

Maumene,    and    the    results    of    his    experiments    pubHshed    in 
Comptes  Rendus,  35,  572. 

When  a  mixture  of  oils  has  been  analyzed  and  the  components 
recognized,  the  proportions  oftentimes  can  be  determined  by  this 
reaction;  that  is  to  say,  suppose  the  oil  under  examination  to 
show  a  rise  of  temperature  of  80°  C,  and  the  oils  found  by 
analysis  to  be  lard  oil  and  menhaden  oil,  their  relative  proportions 
can  be  determined  by  the  following  formula : 


w. 

--■t^:- 

w, 

--'t^- 

Wj  =  proportion  by  weight  of  menhaden  oil  ; 
Wj  =  proportion  by  weight  of  lard  oil  ; 
Wg  =  weight  of  mixture  ; 

t^  =  temperature  of  menhaden  oil  ; 

/j  =  temperature  of  lard  oil  ; 

t^  =  temperature  of  mixture. 

The  method  is  as  follows: 

Fifty  grams  of  the  oil  are  placed  in  a  narrow  tall  beaker  and 
10  cc.  of  chemically  pure  sulphuric  acid  added  drop  by  drop  with 
stirring  and  the  rise  of  temperature  during  the  operation  noted. 

Lard  oil  alone  when  treated  with  sulphuric  acid  gives  a  rise  of 
temperature  of  104°  F. ;  menhaden  oil,  under  similar  conditions, 
a  rise  of  260°  F.  Using  these  values  in  the  above  formula  we 
obtain  54.6  per  cent,  lard  oil  and  45.4  per  cent,  menhaden  oil. 

In  the  mixture  containing  a  mineral  oil  mixed  with  animal, 
marine,  or  vegetable  oil,  the  distinction  would  be  even  more  pro- 
nounced, since  the  mineral  oil  shows  but  a  very  slight  increase  of 
temperature  (generally  from  35°  to  41°  F.).  The  increment 
of  temperature  would  be  dependent  upon  the  other  oil  added  to 
the  mineral  oil. 

Briefly  stated,  the  rise  of  temperature  of  the  following  oils 
would  be : 


EJNGIN EARING   CHEMISTRY 


391 


Lard  oil 

Tallow  oil 

Neatsfoot  oil 

Oleo  oil •■  • 

Elain  oil 

Sperm  oil  

Whale  oil 

Menhaden  oil 

Dog-fish  oil 

Cod  liver  oil 

Crude  cotton-seed  oil  • . 

Rape  oil 

Castor  oil 

Olive  oil 

Resin  oil 

Mineral  lubricating  oil 

Earth  nut 

Sea  elephant 

Corn  oil 


Name  of  observer 


Maumen^ 

°F. 


104 
105-109 

1^3 


Schaedler 


215-217 


136 
116 
107 


217 
156 


118 

109 

82 


i52 


152 


Archbutt 


109 
98 


123 

197 

253-262 


158 


114 
[ 05-1 13 


I 16-140 


Allen 
OF. 


105 


II3-II6 
258 


235 
152-156 


149 

105-109 

64-71 

37-39 


Stillman 
°F. 


102.2 
102 
104 
98 
100 
118 
197 
262 
176 
230 

165 
140 

113 
107 

50 

37 


149 
185 


Attention  is  drawn  to  the  differences  in  the  determination  in 
resin  oil. 

Resin  oil  of  the  first  run  is  white,  opaque,  thick  liquid  con- 
taining all  of  the  water  of  the  resin  from  which  it  is  distilled,  and 
it  is  this  water  that  causes  the  rise  of  temperature  above  10° 
when  the  oil  is  mixed  with  the  sulphuric  acid. 

Resin  oils  of  the  second  and  third  runs  are  clear,  limpid,  dark 
red  colored  fluids,  practically  free  from  water,  and  when  treated 
with  sulphuric  acid  do  not  indicate  more  than  50°  F.  rise  of  tem- 
perature. 

From  these  tests  it  is  concluded  that  both  Schaedler  and  Allen 
tested  resin  oil  that  was  a  mixture  of  the  first  and  second  runs, 
or  of  an  oil  not  properly  separated  into  the  different  distillates. 

8.  Separation  of  Mineral  Oil  from  a  Vegetable  or  Animal  Oil. 

Ten  grams  of  the  oil  are  weighed  out  in  a  dry  weighed  beaker 
(250  cc),  and  to  it  are  added  75  cc.  of  an  alcoholic  solution  of 
potash  (60  grams  of  potassium  hydroxide  to  1,000  cc.  of  95  per 
cent,  alcohol),  and  the  contents  evaporated  until  all  the  alcohol 


392 


e:ngine;e;ring  chemistry 


is  driven  off.  In  this  process,  if  any  animal  or  vegetable  oil  is 
present,  it  is  formed  into  a  soap  by  the  potash,  while  the  mineral 
oil  is  unacted  upon.  Water  (75  cc.)  is  now  added  and  the  ma- 
terial w^ell  stirred  to  insure  complete  solution  of  the  soap,  and 
then  it  is  transferred  to  a  separatory  funnel  (Fig.  78),  75  cc.  of 
sulphuric  ether  added,  corked,  the  liquid  violently  agitated  and 


Fig.  78. 

allowed  to  stand  for  12  hours.  Two  distinct  liquids  are  now 
seen,  the  lower,  the  solution  of  the  soap,  the  upper,  the  ether  solu- 
tion (colored,  if  mineral  oil  is  present,  colorless,  if  not).  The 
aqueous  solution  is  drawn  off  in  a  No.  3  beaker,  the  ethereal  solu- 
tion remaining  in  the  separatory  funnel.     The  former  is  placed 


^NGINKEJRING   CHEMISTRY  393 

on  a  water-bath,  heated  for  half  an  hour,  and  until  all  traces  of 
ether  (which  is  absorbed  by  the  water  in  a  very  small  amount) 
is  gone. 

The  solution  is  allowed  to  cool,  diluted  somewhat  with  water, 
and  made  acid  with  dilute  sulphuric  acid.  Any  animal  or  vege- 
table oil  present  will  be  indicated  by  a  rise  of  the  fatty  acids  to 
the  surface  of  the  liquid.  (In  this  reaction  the  sulphuric  acid  de- 
composes the  soap,  uniting  with  the  potash  to  form  a  sulphate  of 
potash  and  liberating  the  fatty  acids  of  the  oil.) 

If  it  be  desired  to  weigh  the  fatty  acids,  proceed  as  follows : 

Weigh  carefully  about  5  grams  of  pure  white  beeswax,  place 
it  in  the  beaker  upon  the  suface  of  the  oil  and  water,  and  bring 
the  contents  nearly  to  boiling;  the  melted  wax  and  fatty  acids 
unite;  allow  to  cool,  remove  the  wax,  wash  with  water,  dry  be- 
tween folds  of  filter-paper,  and  weigh.  The  increase  in  weight 
of  the  wax  over  its  original  weight  gives  the  weight  of  the  fatty 
acids  of  the  animal  or  vegetable  oil  in  the  lubricating  oil.^ 

Another  method  of  determining  the  weight  of  the  fatty  acids 
after  saponification  is  given  on  page  397. 

The  weight  obtained  must  be  multiplied  by  the  factor  0.97, 
since  the  fatty  acids  exist  in  the  oil  as  anhydrides  and  not  as 
hydrates,  the  latter  being  the  form  in  which  they  are  weighed. 

Instead  of  weighing  the  animal  or  vegetable  oil,  some  chemists 
prefer  to  make  use  of  the  ether  solution,  determining  the  hydro- 
carbon oil  directly ;  in  which  case  proceed  as  follows : 

After  drawing  off  the  soap  solution  from  the  separatory  funnel 
the  ether  solution  is  run  into  a  weighed  flask  (about  250  cc.) 
and  the  ether  distilled  off.  The  residue  in  the  flask  now  consists 
of  the  mineral  oil  and  some  water. 

It  is  quite  difficult  to  get  rid  of  all  this  water.  Direct  heating 
is  inadmissible,  since  the  water  spurts  up  throwing  the  oil  out  of 
the  flask  which  is  lost.  This  can  be  overcome  by  placing  a  glass 
tube  through  the  stopper,  in  shape  of  the  letter  S.  Any  oil 
ejected  against  the  tube  or  cork  cannot  escape,  but  returns  to  the 
base  of  the  flask,  while  the  heat  is  gradually  increased  in  the  flask 

^  Determination  of  Soap  in  lyubricating  Oils,  /.  Soc.   Chem.  Ind.,   1896,  p.   382. 


394 


e;nginee:ring  che;mistry 


and  the  water  vaporized  and  passed  out  through  the  tube;  three 
or  four  weighings  are  generally  required  before  a  constant  weight 
is  obtained.  The  former  process  is  preferable,  since  it  is  per- 
formed much  more  rapidly  than  the  latter,  and  also  the  animal 


Fig.  79.  Fig.  80. 

or  vegetable  oil  is  positively  shown,  and  generally  can  be  identi- 
fied ;  also  many  lubricating  oils  contain  as  high  as  20  per  cent,  of 
hydrocarbon  oil,  volatile  at  or  below  212°  F.    It  is,  of  course,  in 


EJNGINEERING   CHEMISTRY 


395 


the  ether  solution,  and  when  the  water  is  expelled  from  the  oil, 
after  the  ether  has  been  driven  off,  a  large  proportion  of  the 
volatile  hydrocarbon  is  also  evaporated.  If  now  the  animal  or 
vegetable  oil  is  not  also  determined,  a  serious  mistake  would  be 
made ;  vis.,  reporting  20  per  cent,  of  animal  oil  when  it  was  vola- 
tile mineral  oil. 


Fig.   81.  Fig.   82. 

The  fatty  acids  in  another  sample  of  the  oil  are  separated  and 
subjected  to  qualitative  test  for  identification  of  the  oil  from 
which  they  are  derived.  These  tests  comprise  determination  of 
melting-point,  and  congealing  point,  iodine  absorption,  and 
Maumene's  test  (rise  of  temperature  upon  addition  of  sulphuric 
acid). 

There  are  several  methods  of  determining  the  melting-point  of 
the  fatty  acids.    Where  a  considerable  amount  of  the  fatty  acids 


396 


ENGINEERING   CHEMISTRY 


is  available  for  experiment,  the  apparatus  in  Fig.  79  can  be  used. 
The  glass  cylinder  is  filled  one-half  with  fatty  acids,  the  cylinder 
closed  with  a  rubber  stopper,  through  which  a  thermometer  is  in- 
serted, the  bulb  of  which  is  covered  by  the  fatty  acids. 

The  apparatus  is  supported  in  a  beaker  containing  water,  as 
shown  in  Fig.  80. 

If  the  fatty  acids  are  liquid  at  ordinary  temperatures,  the  water 
in  the  beaker  must  be  cooled  with  ice  until  the  fatty  acids  are  con- 
gealed. The  ice  is  removed,  and  the  water  gradually  warmed 
until  the  fatty  acids  become  melted.  At  this  point  the  tempera- 
ture is  taken  and  recorded.  Greater  delicacy  in  the  determination 
of  the  melting-point  is  obtained  by  using  a  small  glass  tube,  sealed 
at  one  end.  The  liquid  fatty  acids  are  placed  in  this  tube,  then 
congealed,  the  tube  tied  to  a  thermometer.  Fig.  81,  and  both 
inserted  in  a  beaker  of  water,  as  shown  in  Fig.  82.  Another 
method  is  to  cover  the  thermometer  bulb  with  a  layer  of  the  solid 
fatty  acids,  about  3  millimeters  thick,  and  immersing  it  in  water; 
gradually  heat  the  water  and  notice  the  temperature  at  which  the 
fatty  acids  leave  the  thermometer  bulb  and  ascend  through  the 
water. 
Table  of  Mei,ting-Points  and  Congealing-Points  of  Fatty  Acids 


Fatty  acids 


Cotton-seed  oil 
Olive  oil  . .  • . 
Rape  seed  oil  • 

Castor  oil 

Sesame  oil  ... 
Cocoanut  oil . . 

Lard 

Tallow 

Wool  fat 

Palm  oil 

Corn  oil 


Melting-point 

°C. 

Congealing  point 
°C. 

330 

30-5 

26.0 

21.0 

20.0 

12.0 

13.0 

30.0 

26.0 

32.0 

24.5 

24.0 

44.0 

39-0 

45-0 

42.0 

42.0 

40.0 

48.0 

43-0 

20.0 

14.0 

The  oils  made  use  of  in  lubrication  can  be  reported  into  two 
groups :  saponifiable  and  unsaponifiable.  To  the  former  belong 
all  the  fatty  oils ;  to  the  latter  the  mineral  and  resin  oils. 

The  method  of  Lux  is  made  use  of  to  determine  if  any  fatty 
oils  are  present  in  a  mineral  oil. 


ENGINKERING   CHEMISTRY 


397 


If  resin  oil  is  suspected  to  have  been  added  to  the  mineral,  it 
can  be  identified  by  the  Liebermann-Storch  reaction,  or  the  pro- 
cess of  E.  Valenta  can  be  used. 

The  Liebermann-Storch  reaction  for  detection  of  resin  oils : 

One  to  two  cubic  centimeters  of  the  oil  under  examination  are 
shaken  with  acetic  anhydride  at  a  gentle  heat;  after  cooling,  the 
acetic  anhydride  is  drawn  off  by  means  of  a  pipette,  and  tested  by 
adding  i  drop  of  concentrated  sulphuric  acid.  If  resin  oil  is  pres- 
ent, a  fine  violet  (fugitive)  color  is  immediately  produced.  This 
test  is  thoroughly  reliable  for  the  detection  of  resin  oil  in  mineral 
oil. 

These  three  tests  will  indicate,  qualitatively,  the  presence  of 
any  fatty  or  resin  oil  in  a  mineral  oil.  It  is  rarely,  in  the  better 
class  of  lubricating  oils,  that  more  than  one  oil  is  added  to  a  min- 
eral oil,  such,  for  instance,  as  lard  oil,  or  tallow,  in  which  case 
saponification  easily  separates  the  two  oils,  and  identification  of 
each  by  special  tests  can  be  made. 


Twenty  grams  of  the  oil  are  weighed  in  a  No.  3  beaker,  100  cc.  of  an  alcoholic  solution 
of  potash  (80  grams  potassium  hydroxide  to  i  liter  alcohol  of  98  per  cent.)  are  added,  and 
heat  applied  with  stirrifl^  until  the  alcohol  is  all  driven  off;  add  100  cc.  water,  heat  with 
agitation,  cool,  add  50  cc.  ether,  transfer  to  separatory  funnel,  stopper,  shake  well  and 
allow  to  stand  2  hours.    Draw  off  the  soap  solution. 


1.  Soap  Solution  (Containing  thefatty  acids 
of  the  lard  and  cotton-seed  oils).  Heat 
10  minutes  nearly  to  boiling,  cool,  acid- 
ify with  dilute  sulphuric  acid,  allow  to 
stand  a  few  hours;  collect  the  separated 
fatty  acids ;  determine  their  weight, 
then  test  as  follows : 

First  portion;  Determine  the  "melting 
point." 

Second  portion  :  Determine  the  iodine  "ab- 
sorption" and  their  rates  by  formula  : 
x={l-n) 
X  =  m  —  fi 


2.  Ether  Solution  remaining  in  the  sepa- 
ratory funnel  is  transferred  to  a  flask, 
the  ether  distilled  and  the  mineral  oils 
weighed. 


When,  however,  the  oil  added  to  the  mineral  oil  itself  contains 
an  adulterant,  such  as  lard  oil  to  which  cotton-seed  oil  has  been 
added,  then  the  fatty  acids  separated  by  saponification  will  re- 
quire a  more  extended  examination  to  prove  the  presence  of  both 
lard  oil  and  cotton-seed  oil. 

The  preceding  skeleton  scheme  is  given  to  show  the  applica- 
tion of  the  above  upon  a  lubricating  oil  that  qualitative  analysis 
has  shown  to  contain  mineral  oil,  lard  oil  and  cotton-seed  oil. 


398  e;ngine:e;ring  chemistry 

There  are  several  methods  for  the  quantitative  determination 
of  the  amounts  of  vegetable  and  animal  oils  when  mixed  with 
each  other  or  when  the  mixture  is  incorporated  with  a  mineral 
oil.  The  determination  of  the  iodine  absorption  is  the  most  deli- 
cate and  correct  provided  no  fish  blubber  or  olive  oils  are  present. 

If  the  fatty  acids  have  been  separated  by  saponification,  from 
a  mineral  oil,  this  iodine  value  can  also  be  determined. 

The  method  of  Salkowski^  depends  upon  the  fact  that  vege- 
table oils  (except  olive)  contain  phytosterol  and  that  animal  fats 
(butter  excepted)  are  free  from  it,  containing  cholestrol,  the 
latter  not  being  present  in  vegetable  oils. 

Fifty  grams  of  the  oils  are  saponified  with  alcoholic  potash; 
the  soap  solution  is  diluted  with  a  liter  of  water  and  250  cc.  of 
ether  added.  When  the  two  layers  have  separated,  the  aqueous 
layer  is  run  off  and  the  ethereal  liquid  filtered,  and  evaporated  to 
a  small  bulk.  To  insure  complete  absence  of  unsaponified  fat, 
it  is  best  to  saponify  again  with  alcoholic  potash  and  to  repeat 
the  exhaustion  with  ether.  The  ethereal  layer  is  then  washed 
with  water  and  the  ether  evaporated  in  a  deep  basin.  The  residue 
is  next  dissolved  in  hot  alcohol,  the  solution  boiled  down  to  i  or 
2  cc.  and  the  residue  allowed  to  cool.  If  phytosterol  or  choles- 
terol be  present,  crystals  will  separate  out.  They  are  dried  on 
unglazed  porcelain  and  their  melting-points  determined. 

The  saponification  value  of  oils  is  often  made  use  of  for  identi- 
fication; but  as  this  value  varies  with  the  age  of  the  oil,  it  is  ex- 
tremely difficult  to  obtain  concordant  results,  and  as  the  majority 
of  oils  have  a  saponification  value  of  193,  excepting  rape  seed  oil 
and  castor  oil,  which  are  lower,  it  cannot  be  relied  upon.  It, 
however,  is  of  no  value  in  determining  the  amount  of  liquid  waxes 
in  the  presence  of  oils. 

Gumming  Test. 

This  test  gives  an  indication  of  the  amount  of  certain  changes 
that  may  be  expected  in  a  mineral  oil  when  in  use.  These 
resinified  products,  resulting  from  use,  increase  the  friction  of 
the  revolving  or  rubbing  surfaces. 

'  Benedikt's  "Oils,  Fats,  and  Waxes,"  p.  255. 


ENGINEERING   CHEMISTRY  399 

It  is  also  a  measure  of  the  amount  that  an  oil  will  carbonize 
in  a  gas  or  gasolene  engine  cylinder.  It  is  applied  after  the 
manner  of  the  elaiden  test,  by  thoroughly  mixing  together  in 
a  cordial  glass  5  grams  of  the  oil  with  11  cc.  of  nitrosulphuric 
acid  and  keeping  the  mixture  cooled  in  a  pan  of  water  at  10°  to 
15°  C.  Brownish  spots  or,  in  case  of  bad  oil,  masses,  form 
around  the  edges  and  become  red  in  the  course  of  two  hours. 

As  has  been  shown  by  long  experience,  the  oil  showing  the 
least  tar  or  gum  is  the  best  oil;  it  also  absorbs  the  least  oxygen. 

The  nitrosulphuric  acid  is  made  by  saturating  sulphuric  acid 
of  1.47  specific  gravity  cooled  to  0°  C,  with  nitric  oxide  (NO). 
(Amer.  Soc.  Testing  Materials.) 

SUI.PHUR  Test.^ 

Proceed  as  follows:  A  portion  of  a  sample,  0.7  to  o.i  gram, 
is  burned  in  a  calorimetric  bomb  containing  10  cc.  of  water  and 
oxygen  under  a  pressure  of  30  atmospheres.  A  lower  pressure 
sometimes  gives  inaccurate  results.  If  the  sample  contains  more 
than  3  per  cent,  of  sulphur  the  bomb  is  allowed  to  stand  in  its 
water  bath  for  15  minutes  after  ignition  of  the  charge.  In  case 
the  sulphur  content  is  as  high  as  5  per  cent.,  oxygen  under 
pressure  of  40  atmospheres  is  used.  With  these  high  pressures 
in  a  Berthelot  bomb  of  500  to  600  cc.  capacity,  repeated  trials 
have  failed  to  show  even  traces  of  carbon  monoxide  or  sulphur 
dioxide.  If  a  smaller  bomb  of  about  175  cc.  capacity,  such  as 
the  Peters  or  Kroker,  is  used,  incomplete  combustion  from  a 
lack  of  oxygen  may  result  if  too  large  a  sample  is  taken. 

After  cooling, — 15  minutes  is  usually  enough, — the  bomb  is 
opened  and  its  contents  are  washed  into  a  beaker.  If  the  bomb 
has  a  lead  washer,  5  cc.  of  a  saturated  solution  of  sodium  car- 
bonate is  added,  the  contents  are  heated  to  the  boiling  point, 
boiled  for  10  minutes,  and  are  then  filtered.  This  operation  is 
necessary  to  decompose  any  lead  sulphate  from  the  washer.  The 
united  washings  are  then  filtered,  acidified  with  hydrochloric 
acid  boiled  to  expel  all  carbonic  acid,  and  the  sulphuric  acid 
content  is  determined  in  the  usual  way  with  barium  chloride. 

^  Allen  and  Robertson,  Technical  Paper  No.  36,  Bureau  of  Mines,  p.    10. 


400  ENGINEERING   CHEMISTRY 

Gravimetric  determination  is  preferred  to  volumetric,  because 
the  nitrogen  contained  in  the  air  originally  4n  the  bomb  is  oxid- 
ized in  part  to  nitroacids,  which  cause  a  small  error  if  the  volu- 
metric determination  alone  is  used.  The  sulphur  content  of  any- 
combustible  material,  from  light  gasolenes  weighed  in  a  tared 
gelatin  capsule  to  solid  bitumens  and  cokes,  can  be  readily  de- 
termined by  this  method. 

This  method  of  burning  in  a  bomb  is  accurate,  practicable, 
and  rapid,  and  is  recommended  in  preference  to  all  of  the  other 
methods  there  described.  The  calorimetric  determination,  if  de- 
sired, can  be  made  at  the  same  time. 

Test  for  Water.^ 

Dilute  the  oil  with  an  equal  volume  of  benzene  and  whirl  it 
vigorously  in  a  centrifuge  until  the  separated  layer  of  water  does 
not  appear  to  increase  in  volume.  However,  as  water  is  some- 
what soluble  in  any  diluent  used  and  also  in  oils,  a  portion  of 
the  water  content  will  fail  to  appear;  consequently  the  method 
in  which  a  diluent  is  used  can  not  be  considered  accurate.  It 
is  advisable  first  to  agitate  the  diluent  vigorously  with  water  and 
then  to  separate  with  the  centrifuge  in  order  to  saturate  it  with 
water  before  using. 

Groschuff^  states  that  lOO  grams  of  benzene  will  dissolve 
0.03  gram  of  water  at  3°  C.  and  0.337  gram  of  water  at  yy^  C, 
whereas  petroleum  products  (density  0.792)  will  dissolve  from 
0.0012  gram  at  2°  C.  to  0.097  gram  at  94°  C. 

Alternate  Method. — The  water  content  may  be  accurately  and 
conveniently  determined  during  the  course  of  an  ordinary  dis- 
tillation in  the  following  manner : 

Two  hundred  grams  of  the  sample  are  weighed  into  a  ^- 
liter  distilling  flask  and  the  distillation  carried  out  in  the  ordi- 
nary manner  at  the  rate  of  i  drop  of  distillate  per  second. 
The  distillation  can  be  performed  most  accurately  in  an  electric 
still.  At  temperatures  between  90°  and  150°  C.  the  water  distills 
over  and  can  be  removed  from  the  receivers  by  means  of  a  micro- 

^  Allen  and  Jacobs,  Technical  Paper  No.  25,  Bureau  of  Mines,  p.  5. 
2  E.    Groschuff,    "The    Solubility   of   Water   in    Benzene,   Petroleum,   and   Paraffine 
Oil,"  Chemical  Abstracts,  Vol.  5,  p.  2550   (Aug.   10,   191 1). 


DNGINKERING    CHEMISTRY 


401 


pipette  and  weighed.  Usually  a  few  drops  of  water  adhere  to 
the  condenser  and  fail  to  run  into  the  receivers;  in  this  event  a 
small  pellet  of  absorbent  cotton,  moistened  with  water,  squeezed 
as  dry  as  possible,  and  weighed,  is  fastened  to  a  wire  and  run  up 
into  the  condenser  to  remove  these  last  traces  of  water.  The  in- 
crease in  weight  of  the  cotton  pellet,  figured  at  water,  is  added 
to  the  weight  of  the  water  in  the  receivers. 

With  an  oil  containing  considerable  water,  it  is  advisable  to 
cause  a  slow  current  of  dry,  inert  gas,  such  as  carbonic  acid,  to 
bubble  through  the  oil  in  the  distilling  flask  to  carry  off  the  vapors 
of  oil  and  water  as  soon  as  formed.  The  gas  current  will  reduce 
bumping  and  overheating  of  the  oil  to  a  minimum. 

The  condenser  must  also  be  kept  well  cooled  throughout  the 
distillation.     This  method  is  accurate  to  less  than  0.03  per  cent. 

GasoIve:ne  Test. 
Dissolve  10  cc.  of  the  oil  in  90  cc.  of  86°  to  88°  gasolene  (from 


t 

sk 


Fig.  83. 


Pennsylvania  crude)   in  the  graduated  tube^  shown  in  Fig.  83. 

^  The  flat  tube  originally  proposed  by  Conradson  cannot  be  obtained  on  the  market. 
26 


402 


ENGINEERING    CHEMISTRY 


Allow  to  stand  i  hour  at  70°  F. ;  not  more  than  5  per  cent,  of 
flocculent  or  tarry  matter  should  have  settled  out.  If  the  test  is 
first  applied  to  the  oil  before  making  the  flash  test  and  again 
after  this  test,  it  shows  the  extent  to  which  the  oil  is  changed 
upon  heating.  Other  things  being  equal,  the  oil  which  is  changed 
the  least  is  the  best  oil. 

MiCROscopiCAE  Examination. 

Put  a  few  drops  of  the  well-mixed  oil  on  a  slide  and  note  the 
nature  of  the  suspended  matter — whether  carbonaceous  specks, 
flakes  of  parafline,  which  disappear  on  warming,  or  foreign  mat- 
ter. Polarized  light  is  a  great  aid  in  detecting  parafline  crystals, 
showing  them  white  on  a  black  background.     The  polariscope  is 


Fig.  84. — "Gray"  carbon  residue  flask. 

excellent  for  this  same  purpose,  showing  them  when  it  is  im- 
possible to  see  them  with  direct  light. 

Carbon  Residue  Test. 

Gray's  Method. — To  a  tared  i -ounce  flask  of  the  dimensions 
shown  in  Fig.  84  add  25  cc.  of  the  oil  to  be  tested  and  weigh. 
Wrap  the  neck  of  the  flask  with  asbestos  paper  as  far  down  as 


KNGINEE^RING    CHEMISTRY  403 

the  side  arm.  Stopper  tightly  with  a  good  cork.  Connect  to  a 
small  aerial  condenser  by  plugging  the  space  with  asbestos  or 
glass  wool.  Provide  a  shield  which  will  protect  the  flame  and 
the  flask  up  to  the  side  tube.  Using  the  flame  of  a  good  Bunsen 
burner,  heat  the  flask  so  that  the  first  drop  of  distillate  will 
come  over  in  approximately  5  minutes.  Continue  the  distilla- 
tion at  such  a  rate  that  i  drop  per  second  will  fall  from  the 
end  of  the  condenser.  As  the  end  of  the  distillation  approaches, 
increase  the  heat  just  enough  so  that  no  heavy  vapors  are  allowed 
to  condense  and  drop  back  into  the  flask,  continue  increasing  the 
heat  until  the  flask  is  enveloped  in  the  flame,  and  hold  the  tem- 
perature 5  minutes.  Allow  the  flask  to  cool,  remove  the  asbes- 
tos covering  and  cork,  and  burn  out  completely  the  carbon  and 
oil  in  the  neck  as  far  down  as  the  side  tube,  and  in  the  side  tube. 
Heat  the  bottom  of  the  flask  until  no  more  vapors  are  given  off. 
Cool  and  weigh. 

FixDD  Carbon  in  OiIv. 

Residues — Petroleum,  Pitch,  etc. — This  is  done  in  the  same 
manner  as  the  determination  of  fixed  carbon  in  coal,  as  described 
on  page  2. 

Estimation  oi^  Paraffins  in  Mine;rai,  O11.S. 

The  following  method  is  due  to  Holde  (after  Engler  and 
Bohm)  : 

Ten  to  20  cc.  of  oils  poor  in  paraffine  (Russian  distillates,  etc., 
setting  below  — 5°  C),  or  5  grams  of  such  as  are  rich  in  that 
constituent  (American,  Scotch,  or  Galician  oils  setting  at  or 
above  0°  C),  are  treated,  at  the  ordinary  temperature,  with  a 
mixture  of  98.5  per  cent,  alcohol  and  anhydrous  ether  (1:1) 
until  a  clear  solution  is  obtained.  The  liquid  is  cooled  in  a  freez- 
ing mixture  of  ice  and  salt  to  about — 20°  C,  when  more  alcohol 
ether  is  gradually  added,  with  thorough  agitation,  until  no  oil 
drops,  but  only  solid  paraffine  flakes  or  crystals  remain  in  sus- 
pension, and  then,  while  still  cooled  to  at  least  — 19°  to  — 21°  C, 
the  liquid  is  poured  on  to  a  chilled  9-centimeter  filter  paper, 
previously  moistened  with  alcohol  ether  mixture,  which  is  con- 


404  e:ngineering  chemistry 

tained  in  the  apparatus  shown  in  Fig.  72.  The  precipitate  is 
washed  with  cold  { — 19°  to  — 21°  C.)  alcohol  ether  (1:1);  or 
for  soft  paraffine  (2:1)  at  a  temperature  as  much  below 
— 15°  C.  as  possible.  In  the  case  of  soft  paraffine,  the  tempera- 
ture should  average  — 18°  to  — 19°  at  the  highest.  In  washing 
the  precipitate  it  is  repeatedly  stirred  up,  and  as  soon  as  5-10  cc. 
of  the  filtrate  leaves  on  evaporation  only  a  trace  of  fatty  or  paraf- 
fine-like  residue,  solid  and  not  oily  at  the  ordinary  temperature, 
the  washing  is  discontinued. 

If  any  doubt  exists  as  to  the  paraffine  being  thoroughly  freed 
from  oil,  or  if  the  washing  takes  too  long,  the  filter  should  be 
removed  to  another  funnel,  and  the  contents  dissolved  into  a 
small  flask  with  the  least  possible  quantity  of  benzine.  After 
evaporation  of  the  benzine,  the  paraffine  is  redissolved  in  4  to  5 
cc.  of  warm  ether,  which  is  then  mixed  with  twice  its  volume  of 
absolute  alcohol,  vigorously  stirred,  and  cooled  to  — 18°  to  — 20° 
to  reprecipitate  the  paraffine,  which  is  again  filtered  and  washed, 
as  already  described,  until  free  from  oil.  This  reprecipitation 
is  necessary  for  oils  containing  much  soft  paraffine,  otherwise 
so  much  liquid  is  used  in  washing  the  precipitate  that  an  appre- 
ciable quantity  of  paraffine  is  dissolved.  The  purified  paraffine  is 
finally  dissolved  into  a  tared  flask  with  hot  benzine  or  ether, 
which  is  distilled  off,  and  the  residue  is  heated  on  the  steam- 
bath  until  the  smell  of  benzine  or  ether  has  disappeared.  The 
flask  is  then  heated  inside  the  water-oven  for  Yx  hour  and 
weighed  when  cold.  Prolonged  heating  causes  los^  of  paraffine. 
The  whole  operation  occupies  from  i  to  2  hours.  Duplicate  re- 
sults with  the  same  sample  agree  within  0.23  per  cent,  for  hard 
paraffine,  and  0.33  per  cent,  for  soft  paraffine.  Two  samples  of 
Russian  machine  oil  yielded  0.34  per  cent,  and  0.36  per  cent,  of 
paraffine  respectively.  An  American  spindle  oil,  fluid  but  thick 
at  2°  C,  and  which  set  at  0°  C,  was  found  to  contain  4. 11  per 
cent,  of  paraffine. 

Soap  Test. 

The  test  depends  upon  the  fact  that  the  metaphosphates 
of  the  earthy  and  alkali  metals  and  aluminum  are  insoluble  in 


ENGINEERING   CHEMISTRY  405 

absolute  alcohol.  Five  to  lo  cc.  of  the  oil  are  dissolved  in  5  cc. 
of  86°  gasoline  or  ether,  and  15  drops  of  a  saturated  solution  of 
"stick  phosphoric  acid"  in  absolute  alcohol  are  added,  shaken 
and  allowed  to  stand :  the  formation  of  a  flocculent  precipitate 
indicates  the  presence  of  soap.  For  the  accurate  determination 
of  these  soaps  a  known  quantity  of  the  oil  must  be  ignited  and 
the  residue  quantitatively  examined. 

Saponification  Vai,ue. 

This  is  expressed  by  the  number  of  milligrams  of  potassium 
hydrate  necessary  to  saponify  i  gram  of  the  oil.  From  2.5 
to  10  grams  of  the  oil,  according  as  65  to  20  per  cent,  of  sa- 
ponifiable  matter  are  supposed  to  be  present,  are  boiled  with  25 
cc.  N/2  alcoholic  potash  in  a  200-cc.  Jena  Erlenmeyer  flask.  A 
reflux  condenser  is  used  and  the  boiling  may  require  from  5  to 
8  hours.  The  excess  of  alkali  is  titrated  with  N/2  HCl,  using 
phenolphthalein.  The  strength  of  the  N/2  KOH  is  determined 
by  boiling  25  cc.  in  similar  flasks  alongside  of  those  in  which  the 
oil  is  treated  and  for  the  same  length  of  time. 

Alcohol  purified  with  silver  oxide  according  to  Dunlap's 
method^  should  be  used  as  well  as  KOH,  purified  by  alcohol. 
For  heavy  oils,  dissolve  them  in  50  cc.  of  C.  P.  benzol  before 
adding  potash. 

Determination  of  Tarry  Matters  in  PetroIvEum  Products. 

At  present  the  French  volumetric  method  is  exclusively  used, 
and  is  very  simple  in  its  principle  and  practical  application. 
According  to  this  method  the  quantity  of  tarry  matter  in  any 
petroleum  product  is  judged  by  the  increase  in  the  volume  of 
the  sulphuric  acid  or  the  decrease  in  the  volume  of  the  tested 
product,  which  is,  after  being  diluted  with  benzene,  submitted  to 
the  action  of  sulphuric  acid,  which  carbonizes  and  dissolves  the 
tarry  substances.  This  method  is,  as  already  mentioned,  very 
simple  and  easy  in  practice,  but  is  connected  at  the  same  time 
with  a  serious  source  of  errors.  Besides  the  principal  action 
of   carbonizing   and   extracting   the   tarry   substances,    sulphuric 

^Journal  Amcr.   Chem.  Soc,  Vol.   28,  p.   397. 


4o6  ENGINEERING   CHEMISTRY 

acid  also  extracts  unsaturated  hydrocarbons,  polymerises,  others, 
etc.  Thus,  for  instance,  a  simple  experience  will  show  that 
even  perfectly  well  refined  oil  treated  with  sulphuric  acid  de- 
creases in  volume  up  to  8  per  cent.  But  the  incorrectness  due 
to  this  may  be  obviated.  Thus  the  quantity  of  unsaturated  hy- 
drocarbons extracted  by  the  sulphuric  acid  can  be  ascertained 
by  determining  the  iodine  value,  and  this  can  then  be  calculated 
to  an  equivalent  value  in  sulphuric  acid,  according  to  the  very 

simple  formula,  V  =  -^;t,  where  V  is  the  volume  of  sulphuric 

acid,  T  the  iodine  value,  and  d  the  specific  gravity  of  the  sul- 
phuric acid.  In  the  works,  where  a  great  number  of  tests  are 
continually  to  be  made,  the  operation  becomes  very  simple,  as  d 
— the  specific  gravity  of  the  sulphuric  acid  in  use — is  practically 
a  constant,  and  so  is  the  iodine  value  T  for  a  whole  series  of 
products. 

Greases. 

Horace  W.  Gillet  in  the  Journal  of  Industrial  and  Engineering 
Chemistry,  June  1909,  states  as  follows : — "Commercial  greases 
may  be  divided  into  the  following  classes : 

"A.  The  tallow  type:  these  greases  are  made  of  tallow  and 
more  or  less  of  an  alkali  soap,  commonly  the  sodium  or  potassium 
soaps  of  palm  oil,  mixed  with  a  smaller  amount  of  mineral  oil. 
These  were  the  principal  types  of  lubricating  grease  10  or  20 
years  ago,  but  to-day  are  less  used  than  the  greases  of  type  B. 

"B.  The  soap-thickened  mineral  oil  type:  these  are  the  most 
common  journal  greases  of  to-day,  and  are  composed  of  mineral 
oil  of  various  grades  made  solid  by  the  addition  of  calcium  or 
sodium  soaps.    Calcium  soap  is  more  used  than  sodium  soap. 

"C.  Types  of  A  or  B  with  the  addition  of  a  mineral  lubricant 
— usually  graphite,  mica  or  talc. 

"D.  The  rosin-oil  type:  these  consist  of  rosin  oil  thickened  by 
lime,  or  less  commonly,  litharge,  to  which  is  added  more  or  less 
mineral  oil,  either  parafiine  or  asphalt  oils  being  used. 


Engine;e:ring  chemistry 


407 


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408  ENGINEERING    CHEMISTRY 

These  greases  are  sticky,  usually  contain  20  to  30  per  cent,  of 
water,  and  find  their  chief  application  as  gear  greases  where  true 
lubrication  is  not  so  essential  as  prevention  of  wearing  and  rat- 
tling of  the  gears. 

"Some  very  heavy  bearings  are  occasionally  lubricated  with  this 
type  of  grease.  Tar,  pitch,  graphite  and  such  fillers  as  wood  pulp 
and  ground  cork  are  often  put  into  these  gear  greases. 

"E.  Non-fluid  oils :  these  are  thin  greases  stiffened  to  some  ex- 
tent with  aluminum  oleate  or  a  mixture  of  soaps,  as  sodium  and 
calcium. 

"F.  Special  greases,  such  as  a  mixture  of  wood  pulp  and 
graphite,  thin  greases  of  any  of  the  above  types  mixed  with  wool 
or  cotton  fibers,  hot  neck  greases,  freak  greases  containing  rubber, 
etc." 

The  analysis  of  a  lubricating  grease  may  have  one  or  two  ob- 
jects in  view: — to  duplicate  the  grease,  or  to  determine  its  value 
as  a  lubricant.     Without  resorting  to  mechanical   tests   of  the 
actual  friction  reducing  power  of  the  grease  in  question,  the  first 
is  probably  the  easier  problem.     In  the  analysis  of  a  grease,  we 
may  cover  the  following  point : 
Consistency. 
Melting-point. 
Flash-point. 
Content  of  free  acid. 
Amount  and  nature  of  soap. 
Ash,  not  alkali,  from  soap,  nature  and  amount. 

Wool  grease'^  is  used  to  some  extent  in  the  cheaper  grades  of 
lubricants,  the  consumption  for  this  purpose  increasing  yearly. 
It  is  partially  unsaponifiable  and,  if  present,  will  be  found  in  the 
ether  extracts  with  the  mineral  oil,  and  also  in  the  soap  solution, 
in  the  analysis  as  usually  conducted  of  a  mixed  lubricating  oil. 

R.  Krause,  of  Wiltemberger,  proposes  a  lubricant  using  wool 
fat,  as  follows :  An  emulsion  of  wool  fat  in  soda  solution  is 
precipitated  with  concentrated  alum  solution,  whereby  is  obtained 

^  For  method  of  analysis  of  wool  grease   ("Yorkshire  grease")   and  lanoline,  con- 
sult Benedikt  and  Eewkowitsch,  pp.   582-585. 
Gill,   "Oil  Analysis,"   pp.    141-147. 


Engine:ering  chemistry  409 

a  brown  soft,  tenacious  mass  of  aluminum  lanoleate.  This  is 
freed  from  salts  and  soap  by  pressing  and  washing  with  hot 
water,  then  dried  and  finally  added  to  mineral  oils  which  it  is 
desired  to  thicken  for  use  as  lubricants,  solution  being  effected 
by  heat.  One  part  of  aluminum  lanoleate  mixed  with  14  parts 
of  light  Scotch  mineral  oil  with  a  gravity  of  0.855  ^o  0.860  yields 
a  lubricating  oil  with  the  viscosity  of  olive  oil. 

Degras  or  sod  oil  is  a  waste  product  obtained  in  the  chamoising 
process.  It  is  largely  derived  from  whale  or  poor  quality  of 
cod  liver  oil  used  in  chamoising. 

The  English-German  method  of  treating  skins  produces  sod  oil 
as  a  waste  product.  The  French  method  produces  degras.  These 
fats  are  largely  used  in  the  production  of  cheaper  lubricants. 

Bone  fat  is  made  use  of  in  lubrication  mixed  with  mineral  oils. 
It  is  recovered  from  bones  either  by  boiling  with  water  or  ex- 
tracting with  solvents.  It  does  not  readily  become  rancid.  Its 
examination  is  made  similarly  to  that  of  tallow. 

Coefficient  of  Friction. 

The  ratio  of  the  force  required  to  slide  a  body  along  a  hori- 
zontal plane  surface  to  the  weight  of  the  body  is  called  the  coeffi- 
cient of  friction.  It  is  equivalent  to  the  tangent  of  the  angle  of 
repose,  which  is  the  angle  of  inclination  to  the  horizontal  of  an 
inclined  plane  on  which  the  body  will  just  overcome  its  tendency 
to  slide.  The  angle  is  usually  denoted  by  </>,  and  the  coefficient 
by  /. /.  =  tan  <f>  (Kent). 

Of  the  various  machines  used  for  this  purpose  nearly  all  are 
deficient  in  conducting  tests  under  extreme  pressure.  However, 
as  all  the  tests  are  relative,  an  idea  of  the  value  of  a  lubricant 
can  be  formed  by  a  series  of  comparative  tests  upon  the  same 
instrument. 

An  instrument  for  determining  coefficient  of  friction  is  the 
Riehle,  in  use  in  many  railroad  laboratories  in  the  United  States, 
for  testing  lubricants.  The  capacity  is  20,000  pounds;  it  deter- 
mines the  coefficient  of  friction,  the  pressure  per  square  inch  of 
journal  and  records  the  temperature. 


4IO 


ENGINEERING   CHEMISTRY 


Method  of  Testing  Oils  on  Riehle  U.  S.  Standard  Oil  Testing 

Machine. 
The  U.  S.  Standard  "test  bearing"  of  9  square  inches  of  pro- 
jected area  is  used.  The  quantity  of  oil  in  making  tests  (also 
the  time  of  test)  varies  according  to  the  will  of  the  experimenter. 
The  oil  is  applied  from  a  sight-feed  oil  cup,  which  can  be  regu- 
lated; it  is  dropped  on  the  journal  in  front  of  the  "test  bearing" 
and  distributes  itself  along  the  edge  of  it  and  is  carried  under- 
neath the  journal. 


Fig.  85. — Machine  for  Determining  Coefficient  of  Friction  of  Oils. 

When  a  pad  is  used  for  making  oil  tests,  it  is  saturated  with 
oil  and  placed  in  the  drawer  underneath  the  journal.  The  oil 
passes  from  the  pad  to  the  journal  and  is  carried  to  the  under- 
side of  the  "test  bearing."  The  pad  (saturated  with  oil)  must  be 
weighed  before  and  after  the  test.  Whether  the  oil  is  tested  with 
or  without  the  pad,  please  note  the  following  instructions : 

Observe  the  pressure  in  pounds  per  square  inch;  friction  in 
pounds  per  square  inch;  the  temperature  above  the  temperature 
of  the  room ;  the  amount  of  oil  used ;  the  revolutions  per  minute, 
and  total  revolutions  of  machine. 


e;ngine:e;ring  chemistry  411 

When  it  is  desired  to  keep  the  bearing  at  a  uniform  tempera- 
ture water  is  circulated  in  the  journal  by  means  of  the  cooling 
apparatus  provided.  This  is  a  new  feature  in  oil  testing  machines, 
and  is  very  much  appreciated  when  it  is  desired  to  make  uniform 
temperature  tests. 

By  comparison  of  results  obtained  from  tests  made  according 
to  the  above  instructions  the  qualities  of  different  oils  can  be 
determined. 

De:scription  and  Operation. 

This  machine  is  used  to  determine  the  lubricating  properties  of 
various  oils.  The  load  on  the  bearing  is  applied  by  means  of  a 
turnbuckle  connection  between  the  beam  and  lower  lever,  and  is 
weighed  on  beam  by  large  poise.  The  friction  in  pounds  on  the 
periphery  of  the  journal  is  indicated  by  a  poise  on  the  upper  or 
friction  beam,  reading  by  increments  of  i  pound.  The  journal 
of  the  machine  is  mounted  on  four  large  rollers,  which  reduce 
the  friction  and  prevent  its  heating,  which  would  affect  the  re- 
sults of  temperature  tests.  Ball  thrust  collar  bearmgs  prevent 
side  motion  of  the  journal,  and  take  any  thrust  in  this  direction 
which  would  cause  friction. 

The  bearing  to  be  tested  fits  in  a  cap  to  which  the  yoke  frame 
is  attached;  this  yoke  frame  is  fitted  with  two  knife  edges  equi- 
distant from  the  center  of  the  shaft;  two  clevises  join  these  knife 
edges  with  similar  knife  edges  in  the  equidistant  lever  below, 
from  which  connection  is  made  to  the  intermediate  lever  and  the 
load  beam.  The  yoke  frame  is  thus  perfectly  free  to  rotate  about 
the  journal,  and  any  tendency  to  do  so  will  show  on  the  friction 
beam. 

The  instrument  in  general  use,  for  the  friction  tests  of  lubri- 
cants, in  Germany,  is  the  "Mertens-Machine,"     (Fig.  86.) 

In  principle  it  is  a  modification  of  the  Thurston. 

It  is  fully  described  by  D.  Holde  in  his  work — "Untersuchung 
der  Mineralole  und  Fette,"  Berlin,  1909. 


412 


ENGINKEIRING    CHEMISTRY 


An  oil  tested  upon  the  tester  may  show  a  fine  lubricant,  while 
put  under  practical  working  upon  a  freight  car   (for  instance) 


Fig.  86. 


would  prove  vastly  inferior.  This  very  often  happens,  and  it  has 
led  many  engineers  to  test  each  oil  by  a  long  run,  with  the  par- 
ticular kind  of  machinery  upon  which  it  is  to  be  used. 


ENGINEERING   CHEMISTRY  413 

Specifications  for  Engine  Oil  for  the  Department  of  Docks  and 
Ferries,  City  of  New  York. 

Quality  of  Engine  Oil. — The  engine  oil  to  be  furnished  under  this 
contract  shall  be  one  of  the  following  brand  or  brands  equal  thereto  and 
approved  by  the  Engineers : 

"Vacuum  No.  i  Marine  Engine  Oil." 
"Kuhne-Libby  Extra  Marine  Castor  Oil." 
"Leonard  &  Ellis  Valvoline  Engine  Oil." 
"New  York  Lubricating  Oil  Co.'s  Diamond  B  Marengene." 
"Fisk  Bros.'  Luberine  Engine  Oil,"  or  equal. 
Each  can  or  package  of  oil  delivered  under  these  specifications  shall 
be  plainly  marked  with  the  marker's  name  and  the  brand. 

(a)   Oil  must  be  of  the  best  quality  and  pass  satisfactorily. 
(h)  Specific  Gravity. — Must  not  be  less  than  0.9000  at  a  temperature 
of  60°  F. 

(c)  Flashing  Point. — Must  not  be  below  420°  F. 

(d)  Fire  Test. — Must  not  be  less  than  475°  F. 

(e)  Freedom  from  Gumming.^ — Just  sufficient  oil  to  cover  the  bottom 
will  be  placed  in  a  shallow  dish.  This  will  be  heated  to  about  250°  F.,  then 
cooled  slowly.  When  cold  there  must  be  no  gummy  residue  in  the  oil  or 
in  the  vessel.  Oil  must  also  pass  satisfactorily  such  other  tests  for 
gumming  as  may  be  ordered  by  the  engineer. 

(/)  A  common  oil  cup  holding  2  ounces  will  be  filled  with  the  oil ; 
two  threads  of  worsted  will  be  used  as  a  wick,  and  all  the  oil  in  the  cup 
must  feed  through  it ;  the  wick  not  to  be  touched  during  the  trial.  This 
test  to  be  made  at  a  temperature  between  70°  and  90°  F. 

{g)   Cold  Test. — The  oil  must  not  solidif}^  at  a  temperature  of  32°  F. 

{h)  Freedom  from  Acid. — A  small  quantity  of  oil  rubbed  on  poHshed 
brass  or  copper  m.ust  not  turn  the  surface  of  the  metal  green  if  allowed 
to  stand  for  24  hours. 

(i)    Viscosity. — Viscosity  at  70°  F.  must  be  between  800  and  850. 

Specifications  of  Cylinder  Oil. 

(a)  Must  be  a  pure  mineral,  hydrocarbon  oil,  with  a  flash-point  of  at 
least  550°  F. ;  burning-point  to  be  above  600°  F. ;  to  be  free  from  tarry  or 
suspended  matter,  acid  or  alkali,  and  from  mixture  or  adulteration  with 
animal,  vegetable  or  fish  oils,  grease,  lard  or  tallow.  Specific  gravity  to 
be  not  below  0.900  nor  above  0.906  at  a  temperature  of  60°  F. 

{h)  A  flash-point  below  550°  F.,  or  the  presence  of  any  of  the  above 
named  adulterations  or  mixtures,  or  a  gravity  different  from  that  specified, 
will  be  sufficient  to  cause  the  rejection  of  the  oil. 

^  This  gumming  is  often  due  to  the  addition  of  rope  oil. 


414  ^ngine:e:ring  chemistry 

(c)  Flashing  Point. — Heat  a  small  quantity  of  the  oil  in  an  open 
vessel,  not  less  than  12°  per  minute,  and  apply  the  test  flame  every  10°, 
beginning  at  250°  F. 

(d)  Precipitation  Test  for  Tarry  and  Suspended  Matter. — Mix  5  cc. 
of  oil  with  95  cc.  of  88°  gasoline,  and  if  there  is  any  precipitation  in 
ID  minutes  the  oil  must  be  rejected. 

This  test  is  easiest  made  by  putting  5  cc.  of  oil  in  a  100  cc.  graduate, 
then  filling  to  the  mark  with  gasoline  and  thoroughly  shaking. 

(e)  Volatility. — Keep  heated  to  400°  F,  in  an  open  vessel;  it  must 
not  lose  more  than  5  per  cent,  of  its  weight  in  2  hours. 

(/)  To  Test  for  Acid  or  Alkali. — It  will  be  sufficient  to  wash  a  small 
quantity  of  the  oil  with  distilled  water,  then  drain  off  the  water  and  test 
it  with  Utmus  paper. 

Specifications  for  Lubricating  Oil  for  Dynamo  Engines  and  Other 

High-Speed  Engines  Using  Forced  Lubrication,  Issued 

by  the  Navy  Department,  November  17,  1906. 

(Superseding  Specifications  24-O-11  Issued  May  25,  1906.) 

1.  Must  be  a  pure  mineral  hydrocarbon  oil,  free  from  acidity,  adul- 
terations, and  impurities,  with  a  flash-point  (open  cup)  of  at  least  350°  F. ; 
to  be  free  from  saponifiable  substances  of  any  character  whatsoever; 
specific  gravity  to  be  between  0.865  and  0.875  at  60°  F. ;  to  be  purchased 
and  inspected  by  weight,  the  number  of  pounds  per  gallon  to  be  deter- 
mined by  the  specific  gravity  of  the  oil  at  60°  F.  multiplied  by  8.33  pounds, 
the  weight  of  a  gallon  (231  cubic  inches)  of  distilled  water  at  the  same 
temperature. 

2.  Viscosity  (by  Engler  viscosimeter)  as  compared  with  distilled 
water  (49)  at  90°  F. : 

At    90°  F 300  to  320 

At  150°  F 105  to  115 

At  225°  F 65  to  75 

3.  Cold  Test. — The  oil  must  flow  at  a  temperature  of  32°  F, 

4.  Freedom  from  Gumming. — Using  a  single- wick  J/^-pint  brass  oil 
cup  maintained  at  about  140°  F.,  practically  equal  quantities  of  oil  must 
feed  through  the  wick  in  equal  intervals  of  time  for  three  intervals  of 
8  hours  each.  At  the  end  of  test  the  wick  must  be  clean  and  sides  of 
oil  cup  bright  and  clean. 

Inspection  and  Delivery, 

5.  Before  acceptance  the  oil  will  be  inspected.  Samples  of  each  lot 
will  be  taken  at  random,  the  samples  well  mixed  together  in  a  clean 
vessel,  and  the  sample  for  test  taken  from  this  mixture.  Should  the 
mixture  be  found  to  contain  any  impurities  or  adulterations,  the  whole 
delivery  of  oil  it  represents  will  be  rejected,  and  is  to  be  removed  by 
the  contractor  at  his  own  expense. 


ENGINEERING   CHEMISTRY  415 

Specifications  for  Neatsfoot  Oil  Issued  by  the  Navy  Department 
March  24,  1908. 

(Superseding  Specifications  24-O-12  Issued  June  22,  1906.) 

1.  Neatsfoot  oil  must  be  free  from  admixtures  of  other  oils,  and 
must  not  contain  more  acidity  than  the  equivalent  of  2j^  per  cent,  of 
oleic  acid. 

2.  It  must  have  a  cold  test  below  10°  F.,  as  determined  in  the  follow^- 
ing  manner:  A  couple  of  ounces  of  the  oil  will  be  put  in  a  4-ounce 
sample  bottle  and  a  thermometer  placed  in  it.  The  oil  will  then  be  frozen, 
using  a  freezing  mixture  of  ice  and  salt  if  necessary.  When  the  oil  has 
become  hard  the  bottle  will  be  removed  from  the  freezing  mixture  and  the 
oil  allowed  to  soften,  being  stirred  and  thoroughly  mixed  at  the  same 
time  by  means  of  the  thermometer  until  the  mass  will  run  from  one  end 
of  the  bottle  to  the  other.  The  reading  of  the  thermometer  at  this 
moment  will  be  taken  as  the  cold  test  of  the  oil. 

Graphite  as  a  Lubricant. 

Graphite  is  used  either  alone  or  mixed  with  various  oils  and 
greases  as  a  lubricant.  Prof.  W.  F.  Gross,  of  Purdue  University, 
has  made  a  series  of  extensive  experiments  upon-  graphite  as  a 
lubricant,  and  in  his  report,  states : — 

''From  the  earlier  and  rather  limited  uses  of  graphite  in  lubri- 
cation, the  field  has  gradually  widened  to  include  its  use  with  light 
oils,  with  water,  and  in  some  cases,  unmixed  with  other  materials. 
It  is  no  longer  regarded  merely  as  a  material  for  an  emergency, 
but  now  has  a  place  in  the  ordinary  and  usual  routine  of  the  day." 

"Graphite  does  not  behave  like  oil,  but  associates  itself  with 
one  or  other  of  the  rubbing  surfaces.  It  enters  every  crack  and 
pit  in  the  surfaces  and  fills  them,  and  if  they  are  ill-shaped  or  ir- 
regularly worn,  the  graphite  fills  in  and  overlays  until  a  new 
surface  of  more  regular  outline  is  produced.  When  applied 
to  a  well-fitted  journal  the  rubbing  surfaces  are  coated  with  a 
layer  so  thin  as  to  appear  hardly  more  than  a  slight  discoloration. 
If,  on  the  other  hand,  the  parts  are  poorly  fitted,  a  veneering  of 
graphite  of  varying  thickness,  which  in  the  case  of  a  certain 
experiment  was  found  as  great  as  Vie  inch,  will  result.  The 
character  of  this  veneering  is  always  the  same,  dense  in  structure, 
capable  of  resisting  enormous  pressure,  continuous  in  service 
without  apparent  pore  or  crack,  and  presenting  a  superficial  finish 


4l6  DNGINEIERING   CHEMISTRY 

that  is  wonderfully  smooth  and  delicate  to  the  touch."  From  a 
long  and  very  severe  series  of  experiments,  it  seems  safe  to  con- 
clude that  no  journal  is  likely  to  be  damaged  from  overheating  or 
kindred  causes  in  the  presence  of  a  supply  of  graphite.  It  is  a 
fact  worthy  of  all  emphasis  that,  with  solid  brasses,  the  pres- 
ence of  flake  graphite  between  the  rubbing  surfaces  makes  it 
impossible  to  score  or  otherwise  damage  the  surfaces  of  the  bear- 
ings even  though  the  temperature  be  allowed  to  run  high. 

**It  goes  without  saying  that  the  use  of  graphite,  in  service 
which  might  be  rendered  without  any  lubrication  whatever,  is 
justified  by  the  more  perfect  action  and  the  greater  durability  of 
the  parts  affected.  Graphite  alone,  in  service  for  which  it  is 
adapted,  is  to  be  preferred  to  oils  or  greases,  because  of  its 
superior  cleanliness  and  because  of  the  persistency  with  which 
it  remains  in  place  after  being  once  applied. 

"The  experiments  with  flake  graphite  as  a  lubricant  justify  the 
following  important  conclusions : 

(a)  The  addition  of  graphite  to  oil  results  in  a  lower  frictional 
resistance  of  the  journal  than  would  be  obtained  by  the  use  of 
oil  alone. 

(b)  When  graphite  is  used  with  oil,  the  amount  of  oil  required 
for  a  given  service  is  reduced. 

(c)  By  the  use  of  graphite  a  light  or  an  inferior  quality  of  oil 
may  be  employed  for  a  given  service. 

(d)  By  the  use  of  graphite,  water  under  favorable  conditions 
may  serve  as  a  sufficient  lubricant. 

(e)  A  small  amount  of  graphite  only  is  required. 

(/)  The  supply  of  too  much  graphite  unduly  thickens  the  oil 
and  correspondingly  increases  its  internal  friction  due  to  viscosity. 

(g)  The  benefits  derived  from  the  use  of  graphite  persist  long 
after  its  application  has  ceased.  The  supply,  however,  should  be 
constant,  though  small,  for  best  results." 

Even  in  the  cylinders  of  air  compressors  there  is  sufiicient 
moisture  to  constitute  a  lubricating  film  without  oil  when  the 
surfaces  of  the  cylinders  and  pistons  have  been  perfected  by  the 
presence  of  graphite. 


ENGINEERING   CHEMISTRY  417 

Lieut.  H.  C.  Dinger,  U.  S.  N.  states : — Flake  graphite  has  the 
peculiar  properties  of  not  being  affected,  either  chemically  or 
physically,  by  any  temperature  encountered  in  a  cylinder.  It  is 
not  easily  carried  away  from  the  wearing  surfaces,  can  stand  any 
pressure,  and  requires  only  an  infinitestimal  clearance  space  be- 
tween surfaces  by  filling  up  all  the  minute  cavities  and  irregulari- 
ties in  the  surfaces,  giving  in  a  short  time,  a  beautiful,  hard- 
polished  surface  which  requires  relatively  little  lubricant. 

Specifications  for  Lubricating  Graphite  Issued  by  the  Navy 
Department  January  17,  1907. 

1.  It  ma}^  be  of  the  flake  or  amorphous  variety.  Amorphous  graphite 
must  be  ground  fine  enough  to  pass  through  a  No.  20  bolting  cloth. 

2.  Samples  taken  from  any  lot  must  show  upon  analysis  at  least*  85 
per  cent,  of  pure  graphite.  It  must  be  free  from  grit,  dirt,  or  any  other 
deleterious  substance. 

3.  It  must  be  put  up  in  air-tight  rectangular  tin  cans  with  screwed 
tops,  each  containing  i  or  5  pounds,  as  may  be  required. 

4.  Each  can  must  be  marked  with  the  name  of  the  material,  the  trade- 
mark, if  any,  and  the  name  of  the  manufacturer. 

The  Calorific  Power  of  Petroleum  Oils  and  the  Relation  of 
Density  to  Calorific  Power. 

The  purpose  of  this  paper  is  to  put  on  record  the  calorific 
power  of  a  considerable  number  of  representative  American  pe- 
troleum oils  and  to  point  out  an  approximate  relationship  between 
the  density  and  the  calorific  power  of  such  oils.^ 

While  among  the  homologues  of  a  given  series  of  hydro- 
carbons, decreasing  proportions  of  hydrogen  might  be  assumed 
to  involve  an  increase  in  density  and  decrease  in  heat  of  com- 
bustion or  calorific  power,  it  would  not  necessarily  follow  that 
such  a  relation  would  obtain  for  the  mixtures  of  hydrocarbons 
which  constitute  the  crude  petroleums  or  thieir  commercial  pro- 
ducts. Nor  have  we  been  able  to  find  in  the  literature  suffi- 
cient comparable  data  to  give  even  an  approximate  expression 
of  the  quantitative  relation  to  be  expected  between  density  and 
the  calorific  power  of  petroleum  products. 

^A.  C.  Shermann  and  A.  H.  Kropff,  Jour.  Amer.  Chem.  Soc,  Oct.,  1908,  pp.  1626-31. 
27 


4i8 


engine:e:ring  chemistry 


Densities  and  Heats  of  Combustion  Observed  and  Calculated. 


No. 

Specific 
gravity 
l5°/'5°. 

Baum6 
degrees 

Calories 

per 
kilogram 

B.  t.  u. 

per 
pound 

B.  t.  u. 

cal- 
culated 

Percent- 
age error 

Description 

I 

0.7100 

67.2 

11,733 

21,120 

20,938 

—0.91 

Gasolene 

2 

0.7175 

65.1 

11,327 

20,389 

20,854 

+  2.33 

" 

3 

0.7209 

64.4 

11,404 

20,527 

20,726 

+  0.99 

" 

4 

0.7709 

51.6 

11,132 

20,038 

20,314 

4-1.28 

* 

5 

0.7830 

48.8 

11,121 

20,018 

20,2C6 

+  0.92 

Kerosene 

6 

0.7850 

48.35 

11,119 

20,014 

20,194 

40.89 

California  refined 

7 

0.7945 

46.2 

11,128 

20,030 

50,098 

+0.33 

West  Va. 

8 

0.7950 

46.1 

11,186 

20,135 

20,094 

—0.20 

Kerosen 

9 

0.7964 

45.8 

11,242 

20,236 

20,082 

+  0.70 

* 

lO 

0.8048 

440 

11,149 

20,068 

20,010 

—0.29 

Ohio  crude 

II 

0.8059 

43-7 

11,143 

10,057 

19,998 

—0.29 

Penna.  crude 

12 

0.8080 

43.2 

1 1 ,001 

19,802 

19,979 

+  0.88 

California  refined 

13 

0.8103 

42.8 

11,090 

19,963 

19.962 

±0.00 

Kansas  refined 

•     M 

0.8237 

40.0 

10,981 

19,766 

19,850 

+0.42 

West  Va.  crude 

15 

0.8248 

39-7 

11,015 

19,827 

19,838 

+0.05 

California  refined 

i6 

0.8261 

39-5 

11,123 

20,021 

19,830 

—0.95 

West  Va.  crude 

17 

0.8321 

38.2 

10,972 

19-757 

19,778 

+  O.II 

* 

i8 

0.8324 

38.2 

10,990 

19,782 

19,778 

—0.02 

Penna. crude 

19 

0.8418 

36.3 

10,950 

19.710 

19,702 

—0.04 

Ohio  crude 

20 

0.8421 

36.25 

10,997 

19.795 

19,698 

—0.48 

Indian  Territory 

21 

0.8536 

36.0 

11,069 

10,924 

18,690 

—  1. 17 

-x- 

22 

0.8466 

35-4 

10,936 

19.685 

19,666 

— 0.09 

Indian  Territory 

23 

0.8500 

35.7 

10,953 

19,715 

19,638 

-0.38 

California  refined 

24 

0.8510 

34.5 

10,958 

19.724 

19,630 

—0.47 

Kansas  crude 

2S 

0.8514 

34.45 

10,945 

19,701 

19,630 

-0.35 

* 

26 

0.8534 

34.05 

10,991 

19.784 

19,610 

—0.86 

■x- 

27 

0.8580 

33.2 

10,772 

19.389 

19,578 

+0.95 

Kansas  crude 

28 

0.8597 

32.8 

10,766 

19.379 

17,562 

+  0.95 

Illinois  crude 

29 

0.8616 

32.5 

10,967 

19.741 

19.550 

—0.95 

* 

30 

0. 8640 

32.05 

10,867 

19,555 

19.530 

—0.12 

California  refined 

31 

0.8648 

31-9 

10,920 

19,656 

19.526 

—0.65 

Penna.  fuel  oil 

32 

0.8660 

31-65 

10,864 

19.555 

I9,5>6 

—0.19 

Fuel  oil 

33 

0.8670 

31-5 

10,850 

19,530 

19.510 

— O.IO 

Penna.  fuel  oil 

34 

0.8690 

31. r 

10,852 

19.534 

19.494 

— 0.20 

Indian  Territory 

35 

0.8708 

30.8 

10,919 

19.654 

19,482 

—0.86 

* 

36 

0.8712 

30.7 

10,879 

19.614 

19,478 

—0.86 

•X- 

37 

0.8945 

30.1 

10,752 

19.354 

19,454 

+0.50 

Kansas  crude 

38 

08773 

29.6 

10,794 

19,429 

19.434 

+0.03 

Penna.  fuel  oil 

■    39 

0.8800 

29.0 

10,804 

19,447 

19,410 

—0.18 

Kansas  crude 

•    40 

0.8807 

29.0 

10,797 

19.435 

10,410 

—0.47 

* 

41 

0.8810 

28.9 

10,797 

19.435 

19,406 

—0.15 

42 

0.8820 

88.75 

10,913 

19,643 

19,400 

—  1.22 

■X- 

43 

0.8828 

28.7 

10,694 

19.249 

19.306 

+  0.73 

Kansas  crude 

44 

0.8833 

28.5 

10,819 

19,474 

19.390 

—0.42 

¥; 

45 

0.8860 

28.0 

10,808 

19,454 

19.370 

—0.42 

Indian  Territory 

46 

0.8862 

28.0 

10,762 

19,372 

10,370 

— 0  01 

* 

47 

0.8900 

273 

10,788 

19,418 

19,342 

—0.39 

Indian  Territory 

48 

0.8914 

27.1 

10,690 

19,242 

19,332 

+  0.45 

Texas  crude 

49 

0.8970 

26.1 

10,753 

19,355 

19.294 

-0.31 

50 

0.9007 

25.4 

10,755 

19,359 

19,267 

—0.47 

^ 

Enginee:ring  chemistry 


419 


Densities  and  Heats  of  Combustion  Observed  and  Calculated. 

{Co7i  tinned). 


No. 

Specific 
gravity 

Baum^ 
degrees 

Calories 

per 
kilogram 

B.  t.  u. 

per 
pound 

B.  t.  .u 

cal- 
culated 

Percent- 
age error 

Description 

51 

0.9050 

24.7 

10,682 

19,228 

19.238 

+  0.05 

52 

0.9061 

24.45 

10,755 

19.352 

19,228 

—0.63 

* 

53 

0.9076 

24.4 

10,605 

19,089 

19,226 

+  0.69 

Kansas  crude 

54 

0.9087 

24.1 

10,712 

19,282 

19.213 

—0.35 

55 

O.9II4 

23.6 

10,724 

19.303 

19.194 

—0.55 

Kansas  crude 

56 

0.9137 

23.2 

10,571 

19,028 

19,178 

+0.76 

Texas  crude 

57 

0.9153 

22.95 

10,692 

19,246 

19,168 

—0.39 

Texas  crude 

58 

0-9155 

22.9 

16,560 

19,008 

19,166 

-fo.8o 

Texas  crude 

59 

0.9158 

22.9 

10,318 

18,572 

19,166 

+2.58 

California  crude 

60 

0.9170 

22.7 

10,613 

19.  "03 

i9.'57 

-f  0.28 

Fuel  oil 

61 

0.9179 

22.5 

10,433 

18,779 

19.150 

+  1.94 

California  crude 

62 

0.9182 

22.5 

10,547 

18,985 

17,149 

+0.83 

California  crude 

63 

0.9336 

20.0 

10,600 

19,080 

19,048 

—0.16 

Texas  crude 

64 

0.9644 

15.2 

10,327 

18,586 

18,858 

+  1.42 

California  crude 

*  Obtained  by  fractional  distillation  of  comitiercial  fuel  or  gas  oils;  Nos.  4,  25,  36,  44 
and  52  were  the  successive  fifths  from  one  sample;  Nos.  9,  21,  26,  29  and  42  from  a  second; 
Nos.  17,  35,  40,  46  and  50  from  a  third. 

It  will  be  seen  throughout  the  range  of  oils  included  in  the 
table  there  is  a  general  tendency  toward  a  fairly  regular  decrease 
in  calorific  power  as  the  specific  gravity  increases  and  the  Baume 
numbers  decrease. 

In  the  cases  in  which  an  approximate  estimate  of  the  calorific 
power  is  most  likely  to  be  useful,  the  expression  of  density  in 
terms  of  the  Baume  scale  and  of  calorific  power  in  British  ther- 
mal units  per  pound  will  probably  be  most  common.^  By  group- 
ing the  samples  falling  within  certain  limits  of  Baume  density 
and  potting  the  average  figures,  it  was  found  that  the  approxi- 
mate average  relation  between  Baume  density  and  calorific  power 
in  B.  t.  u.  may  be  expressed  as  follows : 

B.  t.  u.  =:  18,650  +  40  (Baume  —  lo). 

This  formula  was  then  applied  to  the  data  of  the  individual 
samples.  In  the  columns  headed  "B.  t.  u.  calculated"  and  ''per- 
centage error"  are  given  for  each  sample  the  calculated  British 
thermal  units  and  the  percentage  dift'erence  between  the  calculated 
and  the  determined  values. 

*  It  should  perhaps  be  noted  that  the  heavier  oils  with  lower  calorific  power  per 
gram  or  per  pound  would  show  higher  calorific  power  per  ^ai/on  than  the  light  oils. 


420  ENGINEERING    CHEMISTRY 

It  will  be  seen  that  the  difference  between  the  calorific  power 
as  determined  in  the  bomb  calorimeter  and  as  calculated  from 
the  formula  here  proposed  is  usually  small.  In  only  Yg  of 
the  cases  is  the  difference  greater  than  i  per  cent.,  in  only  ^/g^ 
is  it  greater  than  2  per  cent. ;  in  no  case  is  it  as  great  as  3  per 
cent.  The  samples  examined  were  all  believed  to  be  of  fair  aver- 
age commercial  purity;  the  discrepancies  might  readily  be  larger 
in  oils  grossly  contaminated  with  water  or  suspended  matter, 
but  the  majority  of  such  cases  could  probably  be  recognized  by 
superficial  examination. 

In  view  of  the  number  of  samples  examined  and  the  fact  that 
about  half  of  them  were  selected  as  representative  of  the  pro- 
ducts of  the  principal  oil-fields  of  the  United  States,  while  the 
remainder  were  taken  at  random  from  commercial  sources,  it 
would  seem  safe  to  infer  for  commercially  pure  samples  of  or- 
dinary American  petroleum  oils,  varying  from  heavy  crudes  to 
gasoline,  the  calorific  power  may  be  predicted  from  the  density 
with  about  as  close  an  approximation  to  accuracy  as  is  usually 
obtained  in  calculating  fuel  values   from  chemical  analysis. 

If  it  be  desired  to  estimate  the  calorific  powder  in  terms  of 
calories  per  gram,  or  to  base  the  estimate  upon  specific  gravity, 
or  both,  it  need  only  be  remembered  that  calories  per  kilogram 

140 

X  1.8  =  B.  t.  u.  per  pound,  and  that  specific  gravity  = ,      p, 

I30~r  B 
according  to  the  standard  used  in  obtaining  the  Baume  figures 
here  given,  or  the  following  estimate  may  be  used,  which  being 
obviously  only  an  approximate  indication,  is  perhaps  less  likely 
to  be  misleading  than  is  a  formula : 

A  sp.  gr.  0.70-0.75  indicates  about  11,700-11,350  cal.  per  kg. 

A  sp.  gr.  0.75-0.80  indicates  about  11,350-11,100  cal.  per  kg. 

A  sp.  gr.  0.80-0.85  indicates  about  11,100-10,875  cal.  per  kg. 

A  sp.  gr.  0.85-0.90  indicates  about  10,875-10,675  cal.  per  kg. 

A  sp.  gr.  0.90-0.95  indicates  about  10,675-10,500  cal.  per  kg. 

Of  the  63  samples  here  examined  which  fall  with  these  limits  of 
specific  gravity,  only  2  fall  outside  of  the  indicated  range  of 
calorific  power  by  as  much  as  100  calories,  and  only  7  by  as  much 
as  50  calories. 


ENGINE^ERING   CHE:mISTRY  421 

Summary. 

Sixty-four  samples  of  petroleum  oils,  ranging  from  heavy 
crude  oil  to  gasoline,  and  representing  the  products  of  the  prin- 
cipal oil  fields  of  the  U.  S.  were  examined  for  calorific  power  by 
combination  in  oxygen  in  the  Atwater-Mohler  bomb  calorimeter 
with  results  ranging  from  10,318  to  11,733  calories  per  kilogram, 
or  18,572  to  21,120  B.  t.  u.  per  pound.  In  general  the  decrease  in 
calorific  power  with  increase  in  specific  gravity  was  fairly  regu- 
lar, so  that  the  relation  between  the  two  may  be  expressed  ap- 
proximately by  means  of  a  simple  formula.  When  the  calorific 
powers  calculated  from  the  densities  by  means  of  this  formula 
were  compared  with  those  actually  determined  it  was  found  that 
in  Vo  of  the  cases  the  difference  was  greater,  and  in  Yg  it  was 
less  than  i  per  cent. ;  in  only  ^/g^  was  it  greater  than  2  per  cent. ; 
in  no  case  was  it  as  great  as  3  per  cent. 

While  it  is  obviously  improbable  that  an  exact  quantitative 
relation  should  exist,  it  is  believed  that  from  the  data  here  given 
the  calorific  power  of  commercially  pure  petroleum  oils  may  be 
predicted  from  the  density  with  a  sufficient  approach  to  accuracy 
for  many  practical  purposes. 

Remarks  on  Lubricants  and  Lubrication. 

Lubricating  oils  are  obtained  from  the  crude  petroleum  by  one 
of  two  general  methods,  i.  e.,  destructive  distillation  and  fractional 
distillation. 

Oils  obtained  by  destructive  distillation  are  vaporized  by  means 
of  fire  only.  After  the  lighter  hydrocarbons  (naphtha,  burning 
oils,  gas  oils,  etc.)  have  been  driven  off,  the  heavier  vapors  con- 
taining hydrocarbons  used  for  the  manufacture  of  lubricating  oils 
are  carried  over  from  the  still  to  the  condenser.  In  so  doing  the 
level  of  the  crude  lowers  in  the  still  and  the  heavier  vapors  come 
in  contact  with  the  comparatively  cool  sides  of  the  still,  fall 
back  across  the  heated  metal  and  become  charred.  Some  of  the 
lubricating  qualities  are  destroyed  in  this  operation.  In  this 
process  petroleum  coke  is  the  final  product. 

^  This  article  was  contributed  by  Lewis  F.  Lyne,  Jr.,  General  Manager  of  the  Oil 
Specialties  &  Supply  Company,  39  Cortlandt  St.,  New  York  City,  N.  Y.,  who  is  con- 
sidered an  authority  on  lubrication. 


422  ENGINEERING    CHEMISTRY 

In  the  process  of  fractional  distillation  the  lighter  hydrocarbons 
(naphtha,  burning  oils,  gas  oils,  etc.)  are  driven  off  by  means 
of  fire  only.  At  this  point  steam  is  introduced.  The  steam 
acts  as  a  carrier  for  the  heavier  vapors.  In  the  condensers,  the 
steam,  having  a  lower  condensation  temperature  than  the  distillate, 
allows  the  heavier  vapors  to  condense  under  a  partial  vacuum.  In 
so  doing  the  fractions  are  brought  over  with  less  charring  and 
nearer  their  original  state.  The  final  product  in  this  process  is 
a  heavy  cylinder  stock. 

Mineral  lubricating  oils  may  be  divided  into  three  general 
classes,  i.  e.,  paraffine  oils,  spindle  oils  and  cylinder  stocks. 

The  paraffine  oils  are  manufactured  by  agitating  the  distillate 
with  sulphuric  acid,  by  means  of  compressed  air,  washing  with 
water  and  neutralizing  with  caustic  soda. 

Spindle  oils  are  refined  by  filtering  the  distillate  under  reduced 
pressure  through  Fuller's  earth. 

Cylinder  stocks  are  obtained,  as  stated  heretofore  as  the  final 
product  of  fractional  distillation.  They  may  be  either  filtered  or 
unfiltered. 

Paraffine  oil  may  easily  be  distinguished  from  spindle  oil  by 
means  of  the  heat  test.  Place  a  small  amount  of  the  oil  in  a 
test  tube  and  heat  over  a  spirit  lamp  or  a  Bunsen  burner.  Note 
the  time  in  which  the  oil  discolors  or  turns  to  a  darker  color.  The 
paraffine  oil  will  discolor  very  quickly  whereas  a  spindle  oil  will 
retain  its  color  for  a  greater  length  of  time  as  compared  with  the 
paraffine  oil. 

Taking  lubricating  oils  as  a  whole  they  may  be  sub-divided  as 
follows: — Cylinder  oils,  machine  or  engine  oils,  compressor  oils, 
dynamo  oils,  internal  combustion  engine  oils,  ice  machine  oils, 
turbine  oils,  hydraulic  press  oils,  roll  oils,  cutting  oils,  and  greases. 
Although  not  used  as  lubricants  the  following  are  used  very  ex- 
tensively, tempering  oils  and  transformer  oils. 

The  conditions  usually  met  in  the  lubrication  of  machinery 
are  as  follows : 

Pressure;  heavy,  medium  or  light. 
Speed ;  high,  medium  or  low. 
Temperature;  high  medium  or  low. 


ENGINEERING   CHEMISTRY  423 

The  viscosity  is  a  most  important  factor  to  be  considered 
when  selecting  an  oil  for  a  specific  purpose.  Although  an  oil  may 
be  of  the  highest  quality  it  may  cause  considerable  trouble  in  the 
operation  of  the  machine,  due  to  the  fact  that  the  viscosity  may  be 
either  too  high  or  too  low  (see  dynamo  oil).  Then  again  the 
viscosity  of  oils  should  be  considered  at  various  temperatures. 
The  temperature  at  the  point  of  application  should  be  determined 
in  order  to  secure  an  oil  viscous  enough  at  that  temperature  to 
insure  proper  lubrication. 

Where  it  is  possible  thermometers  should  be  placed  on  all 
main  bearings,  as  they  are  the  most  efficient  safeguard  against 
overheating.  For  instance,  after  a  plant  has  had  a  general  over- 
hauling, the  bearings  may  have  been  tightened  too  much.  In 
such  a  case  the  error  may  not  be  noticed  until  too  late,  resulting 
in  a  general  shut-down.  Whereas  if  thermometers  had  been 
placed  a  rise  of  say  20°  or  30°  would  give  warning  and  a  heavy 
cylinder  oil  could  be  used  for  a  time  until  normal  temperature 
was  resumed,  or  the  bearing  readjusted. 

Specifications  may  call  for  an  oil  of  a  certain  viscosity  at  70° 
or  100°  F.,  but  the  temperature  of  the  bearing  is  150°  F.  In  this 
case  two  oils  may  be  submitted  which  have  the  same  viscosity  at 
70°  or  100°  F.  and  have  the  same  appearance,  but  one  may  be 
of  a  paraffine  and  the  other  asphaltum  base.  The  viscosity  of  the 
paraffine  base  oil  will  be  lowered  to  some  extent  upon  the  rise  of 
temperature  whereas  in  the  asphaltum  base  oil  the  viscosity  will 
be  lowered  to  a  very  marked  degree,  thereby  not  retaining  vis- 
cosity enough  to  insure  proper  lubrication.  Asphaltum  base  oils 
may  be  generally  recognized  by  the  low  gravity  and  cold  test  and 
high  viscosity,  and  the  rapid  lowering  of  the  viscosity  upon  the 
rise  of  temperature  as  compared  with  a  paraffine  base  oil. 

Cyunder  Oil.. 
Cylinder  oils  may  be  filtered  or  unfiltered.  The  former  is  gen- 
erally olive  green  while  the  latter  is  dark  brown.  Although  a  cyl- 
inder oil  may  be  filtered  it  is  not  necessarily  a  superior  lubricant  to 
the  unfiltered  stock.  When  filtered  the  oil  becomes  lighter  and 
some  of  the  lubricating  hydrocarbons  are  removed.     In  an  unfil- 


424  ENGINEERING   CHEMISTRY 

tered  cylinder  oil  all  of  the  lubricating  ingredients  remain.  How- 
ever, the  unfiltered  stock  must  not  contain  ^ny  impurities  such 
as  tar,  moisture,  or  dirt,  which  may  be  found  in  the  poorer  grades 
of  unfiltered  cylinder  oils. 

Tarry  matter  may  be  found  by  dissolving  5  cc.  of  the  oil  in 
95  cc.  of  a  high  gravity  naphtha  (88°  B.).  If  a  precipitate  is 
noticeable  after  standing  24  hours  it  indicates  the  pres-ence  of 
tarry  matter.  In  some  extreme  cases  it  may  be  detected  by  its 
characteristic  odor. 

If  moisture  is  present  in  quantity  it  may  be  detected  by  dis- 
solving the  oil  in  high  gravity  naphtha  (88°  B.)  until  the  mixture 
is  just  transparent.  Shake  well.  Globules  of  moisture  if  present 
will  fall  to  the  bottom  of  the  container,  while  the  air  bubbles  will 
rise  to  the  top. 

The  presence  of  glue  due  to  improper  barreling  may  be  found 
by  the  irregular  operation  of  the  hydrostatic  sight  feed  cup.  The 
hole  through  which  the  oil  is  forced  by  the  condensed  steam  be- 
comes clogged.  Then  again  the  valves  groan  and  a  surplus  quan- 
tity of  oil  is  necessary  to  overcome  the  difficulty. 

Dirt  of  any  nature,  whether  filings  from  the  steam  pipes,  scale 
from  the  boiler  carried  over  by  the  steam,  or  solid  foreign  sub- 
stances of  any  description  may  be  found  by  filtering  the  oil 
through  a  piece  of  fine  cloth  or  filter  paper.  If  too  viscous  dis- 
solve a  quantity  in  some  high  gravity  naphtha  (88°  B.)  which 
will  permit  the  filtration  of  the  oil.  The  dirt  will  remain  on  the 
cloth  or  filter  paper. 

The  gravity  of  a  cylinder  oil  gives  no  indication  of  the  lubri- 
cating qualities  but  merely  aids  in  determining  the  base  (paraffine 
or  asphaltum)  of  the  crude  from  which  it  was  made. 

The  flash  point  too  is  of  minor  importance  since  it  is  deter- 
mined at  atmospheric  pressure  whereas  the  pressure  in  the  cyl- 
inder is  much  higher,  which  results  in  very  different  conditions. 
However,  the  flash  point  of  the  oil  should  be  sufficiently  high  not 
to  disintegrate  at  the  temperature  of  the  steam  at  the  pressure 
in  qviestion. 

The  cold  test  is  important  only  as  regards  the  storage.     If  the 


EINGINEERING    CHE:mISTRY  425 

store  room  is  subjected  to  low  temperature  a  sufficient  amount 
should  be  kept  accessible  for  the  filling  of  the  lubricator  upon 
short  notice.  In  a  number  of  instances  a  receptacle  containing  a 
sufficient  amount  of  surplus  oil  is  allowed  to  stand  on  or  near 
the  cylinder  of  the  engine  or  on  hot  steam  pipes  in  the  engine 
room. 

Unlike  the  conditions  in  bearing  lubrication,  the  viscosity  and 
lubricating  qualities  are  difficult  to  determine  in  cylinder  lubri- 
cation. 

A  straight  cylinder  oil  should  be  used  in  the  lubrication  of 
steam  cylinders  only  where  superheated  steam  is  used.  Here  the 
cylinder  walls  are  dry  and  the  oil  adheres  to  them.  In  the  case 
of  saturated  steam  the  cylinder  walls  are  moist,  and  as  a  straight 
mineral  oil  will  not  mix  with  water  the  oil  is  washed  off. 

Therefore  a  compound  of  animal  and  mineral  oil  will  give  the 
most  efficient  lubrication,  as  animal  oil  mixes  or  emulsifies  with 
water,  insuring  adhesion  of  the  compound  to  the  cylinder  walls. 

The  moisture  in  the  steam  should  govern  the  percentage  of 
animal  oil  to  be  compounded,  which  should  be  kept  as  low  as 
possible.  Upon  the  application  of  heat  the  animal  oil  liberates 
fatty  acids  commonly  known  as  "free  fatty  acids"  which  have  a 
decided  action  on  metals.  This  factor  cannot  be  given  too  careful 
consideration  as  a  compounded  oil  may  seem  to  give  entire 
satisfaction  for  the  time  being.  But  the  inspection  of  the  cylinder 
walls  after  say  2  or  3  years  of  operation,  finds  them  "honey- 
combed," and  in  some  instances  the  stud  bolts  are  eaten  off.  A 
very  noticeable  effect  of  acidity  in  compounded  cylinder  oils  is 
the  necessity  for  frequent  renewals  of  cylinder  head  gaskets, 
leaky  piston  packing  and  leaky  joints  in  the  exhaust  pipe. 

The  following  are  the  specifications  for  steam  cylinder  oils  used 
by  a  power  corporation  controlling  a  large  number  of  high  pow- 
ered generating  plants : 

Spe)ciFications. 
To  be  a  mixture  of  pure  mineral  hydrocarbon  cylinder  stock 
and  acidless   animal   oil. 

Viscosity  not  to  go  below  170  Tagliabue  at  212°  F.  and  should 


426  ENGINEERING   CHEMISTRY 

show  a  difference  of  not  over  5  per  cent,  in  the  viscosity  due  to  a 
rise  of  10°  F.  (This  oil  to  have  a  viscosity  at  212°  F.  equal  to  a 
sugar  solution  at  70°  F.  Solution  is  made  of  57.1  parts  by 
weight  of  best  refined  granulated  sugar,  42.9  parts  by  weight  of 
water.) 

Gravity  to  be  between  24°  and  26°  B.  at  60°  F. 

Flash  point  not  lower  than  560°  F.  and  burning  point  to  be 
at  least  50°  higher.  Open  test: — not  less  than  50  cc.  of  oil  to 
be  heated  per  minute  until  flash  point  is  reached. 

Should  not  test  more  than  2  per  cent,  by  weight  of  tarry  res- 
inous precipitate  when  tested  by  shaking  5  cc.  of  the  oil  with 
95  cc.  of  88°  B.  naphtha  and  filtered  after  12  hours  standing. 
Should  be  free  from  any  trace  of  mineral  acid  or  more  than 
5  per  cent,  free  fatty  acid  calculated  as  oleic. 

Volatility ;  should  not  lose  more  than  i  per  cent,  per  hour  at  a 
temperature  of  400°  F.  Should  contain  no  adulteration  such  as 
soap  ash,  resin  oil,  gumming  principles,  grit  or  dirt. 

The  following  ingredients  to  be  used  in  making  cylinder  oil 
for  this  company. 

5  per  cent,  acidless  tallow  oil. 
2  per  cent,  neatsfoot  oil. 
93  per  cent.  Pennsylvania  cylinder  stock. 

There  should  be  no  separating  of  stock  after  10  grams  have 
been  in  an  open  vessel  48  hours,  nor  should  there  be  any  tendency 
to  coagulate  at  room  temperature. 

The  conditions  for  the  above  specifications  vary  from  saturated 
steam  at  50  pounds  pressure  to  200  pounds  pressure  with  125° 
of  superheat. 

Most  boiler  compounds  are  composed  chiefly  of  caustic  soda, 
potash,  etc.  When  the  steam  comes  in  contact  with  compounded 
cylinder  oils,  the  animal  oil  is  saponified,  or  in  other  words  soap  is 
formed  which  thickens  and  gums,  leaving  the  mineral  oil,  which 
is  washed  from  the  cylinder  walls.  It  might  be  said  at  this  point 
that  water  is  the  factor  most  detrimental  to  efficient  steam  cylin- 
der lubrication,  especially  when  carrying  caustic  soda  or  potash. 
It  is  recommended  that  the  water  from  the  drain  cocks  on  the 


ENGINDKRING    CHEMISTRY  427 

cylinders  be  tested  from  time  to  time  by  inserting  a  piece  of  red 
litmus  paper  in  the  sample.  If  alkali  is  in  excess  it  will  turn  the 
litmus  paper  blue. 

Steam  traps  are  recommended  where  possible,  as  they  retain 
the  lime,  magnesia  and  silica  which  come  over  in  the  steam  in 
solid  particles  thereby  scoring  the  cylinder. 

The  groaning  of  valves  is  not  always  due  to  a  poor  grade  of 
cylinder  oil.  In  one  case  it  was  found  that  the  slide  valve  had 
attained  knife  edges  due  to  constant  operation.  By  simply  round- 
ing the  edges  by  means  of  a  fine  file  the  difficulty  was  overcome. 

A  method  of  comparing  the  oil  film  of  various  oils  on  cylinder 
walls  is  to  rub  them  with  a  number  of  sheets  of  tissue  paper. 
Take  off  enough  sheets  so  that  the  stain  can  just  be  noticed  on 
the  top  sheet.  Then  run  the  oil  to  be  tested  comparatively  for  the 
same  length  of  time  and  repeat  the  operation  with  the  tissue  paper. 
If  a  thicker  film  remains  on  the  cylinder  wall  a  greater  number 
of  sheets  will  be  stained,  and  this  oil  will  give  better  lubrication 
than  the  original. 

Turbine:  OiIvS. 

Invariably  oil  used  for  the  lubrication  of  steam  turbines 
should  be  a  pure  filtered  mineral  oil.  The  presence  of  adulter- 
ants or  foreign  matter  of  any  kind  will  result  in  an  emulsion 
if  the  steam  comes  in  contact  with  the  oil,  and  the  circulatory 
system  of  lubrication  will  become  clogged. 

The  lighter  bodied  oils  give  the  best  results  because  of  the  very 
high  rate  of  speed.  Then  again  the  lighter  oils  retain  their  vis- 
cosity to  a  higher  degree  than  the  heavier  oils. 

The  most  important  factor  in  turbine  oil  is  that  it  should  sepa- 
rate very  readily  from  water.     (See  motor  oils  for  emulsion  test.) 

The  same  rule  holds  for  reciprocating  engines  with  a  circu- 
latory system  using  an  oil  filter. 

Cutting  O11.S. 

The  objects  of  cutting  oils  are  to  facilitate  a  clean  cutting  of 
the  surface  of  the  metal,  to  overcome  the  chattering  of  the  cutting 
tool,  and  to  carry  off  the  generated  heat. 

The  conditions  vary  in  a  great  many  ways,  from  the  machin- 


428  ENGINEERING    CHEMISTRY 

ing  of  cast  iron  to  the  machining  of  the  parts  for  the  most  ac- 
curate electrical  instruments. 

A  large  furnace  concern  uses  straight  mineral  oil  on  the  taps 
for  the  threading  of  iron  castings  which  compose  the  hot  water 
heaters. 

Lard  oil  is  universally  looked  upon  as  the  most  efficient  cutting 
oil,  but  owing  to  the  high  cost  of  the  best  grade  experiments  were 
made  which  proved  that  a  compound  of  lard  oil  and  a  good  grade 
of  mineral  oil  produced  entirely  satisfactory  results.  The  per- 
centage of  lard  oil  depends  entirely  upon  the  fineness  and  accu- 
racy of  the  work  in  question.  A  concern  manufacturing  most  of 
the  standard  electrical  instruments  uses  a  compound  of  30  per 
cent,  of  lard  oil  and  70  per  cent,  of  a  filtered  mineral  oil. 

However,  for  general  machine  work  a  compound  of  10  to  15 
per  cent,  of  a  good  grade  of  lard  oil  and  the  remainder  of 
medium  bodied  mineral  oil  will  be  found  to  cover  the  general  re- 
quirements of  cutting  oils. 

Ice  Machine  Oie. 

The  principal  requirements  of  oil  for  the  lubrication  of  ice 
machines  are :  flash  point  high  enough  to  withstand  the  heat  gen- 
erated when  the  gas  is  compressed ;  cold  test  low  enough  that  the 
oil  will  not  congeal  at  the  temperature  of  the  expanded  ammonia 
gas.  Hence  the  oil  must  be  so  refined  as  to  have  minimum 
paraffine  content. 

When  condensed  exhaust  steam  is  used  for  the  manufacture 
of  ice  it  is  essential  that  as  little  oil  as  possible  be  used  in  the  lub- 
rication of  the  cylinder  to  avoid  discoloration  of  the  ice. 

Fatty  compounds  should  not  be  used  in  the  lubrication  of  the 
cylinder  as  a  milky  emulsion  hard  to  eliminate  will  be  seen  in 
the  ice  if  the  oil  gets  past  the  piston. 

Transformer  Oies. 

Oil  in  transformers  is  used  as  an  insulating  and  cooling  med- 
ium, therefore  it  should  be  a  pure  mineral  oil  obtained  by  the 
fractional  distillation  of  petroleum,  free  from  any  adulterant. 


£;ngine:ering  che:mistry  429 

As  one  of  the  main  functions  of  the  oil  is  that  of  an  insulator, 
the  dielectric  strength  should  be  very  high. 

The  method  of  testing  transformer  oil  by  the  Westinghouse 
Electric  and  Manufacturing  Co.  is  as  follows : 

(a)  Use  a  transformer  of  at  least  i  kilowatt  capacity,  pro- 
vided with  suitable  means  for  varying  the  voltage  on  oil  testing 
apparatus.    Style  No.  y2,/\2y  (W.  E.  &  M.  Co.). 

(&)  Carefully  clean  oil  testing  apparatus  w^ith  benzine  or  gas- 
oline and  thoroughly  drain.  Use  particular  care  to  see  that  no 
moisture  becomes  mixed  with  the  oil  or  condenses  on  the  ap- 
paratus. 

(<:)  The  temperature  of  the  oil  should  be  between  20°  C. 
(68°  F.)  and  25°  C.  {y]""  F.). 

(c?)  Pour  about  200  cc.  of  oil  into  the  testing  jar  and  adjust 
gap  to  0.15  inch. 

(^)  Apply  the  testing  voltage,  and  raise  rapidly  and  uniformly 
without  opening  the  circuit  until  breakdown  occurs. 

(/)  Agitate  oil  thoroughly,  reset  gap  and  repeat  test,  until  ten 
breakdowns  have  been  obtained.  Take  average  of  ten  tests  as 
breakdown  voltage  of  the  oil. 

(^)  Certain  oil  will  give  a  minute  discharge  spark  between 
the  terminals  at  a  voltage  considerably  lower  than  the  true  break- 
down voltage.  Care  must  be  taken  not  to  mistake  this  discharge 
spark  for  the  breakdown.  The  oil  should  be  moisture  free  or  as 
nearly  so  as  possible. 

The  separative  qualities  vary  greatly  in  diiferent  oils.  Acid 
treated  oils  emulsify,  therefore  a  straight  filtered  oil  is  necessary. 

The  presence  of  traces  of  acid  used  in  the  refining  of  oil  or  of 
alkali  is  not  permissible  for  two  reasons :  First,  the  presence  of 
acid  or  alkali  reduces  the  strength  of  the  dielectric,  and  second, 
they  have  a  corrosive  or  destructive  effect  on  the  materials  of 
which  the  transformer  is  composed. 

The  viscosity  of  transformer  oil  is  of  foremost  importance 
since  one  of  its  main  functions  is  that  of  cooling.  The  more 
viscous  the  oil  the  slower  its  circulation,  hence  the  transfer 
of  heat  will  be  correspondingly  slow.     Heavy  oil  will  not  cir- 


430  ENGINEERING   CHEMISTRY 

culate  freely  through  the  oil  ducts  of  the  transformer,  therefore, 
a  high  temperature  gradient  exists  between  the  oil  and  the  trans- 
former windings. 

Transformer  oil  should  be  free  from  deposit.  The  deposit  is 
objectionable  chiefly  because  it  retards  the  circulation  of  the  oil 
by  clogging  the  oil  ducts.  The  deposit  is  an  indication  that  a 
chemical  decomposition  is  taking  place  and  should  be  rectified 
immediately. 

The  flash  and  fire  points  of  the  oil  are  of  minor  importance  as 
the  maximum  temperature  does  not  exceed  ioo°  F. 

The  loss  of  the  oil  by  evaporation  should  be  very  low  and  if  the 
oil  disappears  rapidly  the  cause  is  probably  due  to  the  oil  syphon- 
ing out  through  poorly  designed  leads,  or  that  the  transformer 
box  is  not  air  tight. 

The  color  of  the  oil  should  be  light  for  inspection  of  the  trans- 
former when  submerged.  Then  again  it  is  sometimes  necessary 
to  make  changes  on  the  terminal  board  below  the  oil  level. 

Dynamo  Oii^. 

The  range  of  sizes  of  dynamos  of  the  present  day  calls  for  oils 
of  a  great  variety.  The  oils,  however,  should  all  be  filtered 
spindle  oils  free  from  any  ingredient  which  tends  toward  gum- 
ming. 

The  bearings  should  be  at  approximately  room  temperature 
and  any  very  noticeable  rise  should  be  looked  after  immediately. 

Hot  bearings  may  be  the  result  of  a  tight  belt,  unequal  air  gaps, 
due  to  the  wear  of  the  Babbitt  metal  in  the  bearing,  high  viscosity 
of  oil,  etc. 

An  instance  is  known  where  a  very  high  grade  oil  was  used 
on  the  bearings  of  a  high  speed  motor,  but  invariably  they  over- 
heated. Upon  close  inspection  it  was  found  that  the  oil  was  so 
viscous  that  it  held  the  oil  rings  stationary.  The  oil  was  drained 
from  the  reservoirs  and  a  lower  viscosity  spindle  oil  was  placed 
therein.  The  motor  was  started,  the  oil  rings  revolved  and  the 
bearings  cooled  down  during  operation. 


DNGINEEJRING    CHEMISTRY  43I 


Compressor  O11.S. 


The  conditions  on  an  air  compressor  vary  to  a  very  marked 
degree  as  compared  with  the  steam  engine. 

The  interior  of  the  cylinder  is  dry  and  warm,  in  some  cases 
very  hot,  the  degree  of  heat  depending  upon  the  pressure  to 
which  the  air  is  compressed.  Hence  an  unadulterated  mineral 
oil  should  be  used  containing  absolutely  no  fatty  oil. 

The  oil  should  have  a  high  flash  point  due  to  the  high  degree 
of  heat  within  the  cylinder.  Great  care  should  be  exercised  on 
this  point.  Serious  accidents  may  take  place  because  an  oil  of  a 
low  flash  point  volatilizes  and  may  be  ignited  by  the  high  degree 
of  heat  resulting  in  cracked  cylinders,  explosions  and  some  times 
total  wrecks  of  plants. 

The  viscosity  of  the  oil  should  be  as  low  as  possible  insuring 
maximum  lubrication.  The  free  carbon  content  should  be  at  a 
minimum,  because  an  oil  which  carbonizes  rapidly  will  tend  to 
clog  up  the  pipes  and  prevent  the  valves  from  closing.  Especial 
care  should  be  exercised  to  keep  out  foreign  matter,  dirt,  grit, 
and  the  like. 

The  oil  should  also  have  a  low  cold  test,  as  the  expanding  gas 
carries  heat  with  it,  resulting  in  a  low  temperature  at  that  point. 

Hardening  and  Tempering  OiIvS. 

The  use  of  oil  in  the  process  of  hardening  and  tempering  steel 
is  a  very  broad  and  delicate  subject  and  the  best  results  can  only 
be  obtained  by  experience  combined  with  experiment. 

When  the  oil  is  used  for  the  purpose  of  hardening  steel,  it 
serves  as  a  quenching  medium,  whereas  in  tempering,  it  is  a 
heated  bath  in  which  the  steel  is  submerged  to  bring  it  up  to  the 
required  temperature. 

By  using  oil  lesser  degrees  of  hardness  are  obtained  than  when 
water,  brine,  mercury  or  similar  mediums  are  employed.  The 
heat  is  dissipated  less  rapidly  and  the  action  is  not  so  severe.  In 
this  case  the  result  desired  is  the  essential,  taking  into  considera- 
tion the  quality  and  shape  of  parts  to  be  hardened  and  the  de- 
gree of  hardness  required. 


432  i;ngine;e:ring  chemistry 

There  still  exist  many  differences  of  opinion  among  steel  men 
versed  in  this  subject  regarding  the  proper  and  most  efficient 
quenching  medium  and  it  is  also  true  that  though  but  one  oil  be 
used  a  wide  range  of  results  may  be  obtained  by  different  opera- 
tors. It  is  evident  therefore  that  the  results  are  due  chiefly  to 
the  manner  in  which  the  oil  is  applied,  the  temperature  to  which 
it  is  heated  before  quenching,  and  the  length  of  time  of  sub- 
mersion. 

The  tendency  to-day  is  to  disregard  all  of  the  old  theories  and 
"hobbies"  and  use  a  straight  mineral  oil  of  a  high  flash  point. 

The  flash  point  is  one  of  the  most  important  points  to  be  con- 
sidered in  selecting  an  oil  for  the  above  use.  It  must  be  high 
enough  so  that  the  oil  will  not  disintegrate  and  volatilize  at  a  rapid 
rate.  In  some  special  cases  a  special  brand  of  oil  such  as  sperm, 
cotton-seed  or  lard  oil  is  used,  but  in  common  practice,  the  cost 
does  not  warrant  its  use,  hence  a  straight  mineral  oil  will  give 
the  most  satisfactory  and  efficient  results. 

Motor  O11.S. 

The  factor  which  demands  the  most  attention  in  the  operation 
of  internal  combustion  engines  is  that  of  lubrication. 

Unlike  the  general  scope  of  machine  lubrication  motor  oils 
must  withstand  a  very  high  degree  of  heat  and  with  this  point  in 
view  the  process  of  manufacture  must  be  such  that  oils  contain 
no  detrimental  ingredients. 

At  present  there  are  two  ways  in  which  motor  oils  are  manu- 
factured :  One  by  destructive  distiflation  and  treatment  with 
sulphuric  acid  and  an  alkali ;  the  other  by  steam  distillation  and 
filtration  through  Fuller's  earth. 

The  former  is  the  cheaper  method  of  manufacture  but  by  far 
the  more  costly  in  the  end  to  the  operator.  The  distillate  is 
treated  with  sulphuric  acid  to  throw  down  unstable  compounds 
and  at  the  same  time  free  carbon  is  carried  down  with  them. 
After  being  washed  with  water,  an  alkali  is  introduced  to  neu- 
tralize the  acid  that  may  remain.  Thus  salts  of  the  alkali 
are  formed,  which  cannot  be  entirely  removed.  Hence  when 
subjected  to  a  high  degree  of  heat  in  the  cylinders  a  chemical 


ENGINKERING    CHEMISTRY  433 

reaction  takes  place  forming  compounds  that  react  on  the  cylin- 
der walls,  piston  and  piston  rings  causing  them  to  corrode  and 
leak.  Excess  carbon  is  formed,  which  scores  the  cylinders  and 
pistons. 

On  the  other  hand  the  oil  made  by  steam  distillation  is  filtered 
under  reduced  pressure  through  Fuller's  earth.  This  is  entirely 
a  mechanical  process  and  no  adulterants  are  used  during  the 
treatment.  Hence  there  are  no  chemical  reactions  in  the  cylin- 
ders and  carbon  deposit  is  reduced  to  a  minimum. 

Fatty  compounds  of  any  description  should  never  be  used  on 
account  of  the  liberation  of  fatty  acids  under  heat. 

The  base  of  the  petroleum  from  which  the  motor  oil  is  made 
should  be  carefully  considered,  that  is,  whether  paraffine  or  as- 
phaltum.  The  former  has  been  proven  by  extensive  tests  to  be 
the  more  satisfactory. 

Heat  Test. — The  method  of  manufacture  of  the  oil,  that  is 
whether  acid  treated  or  filtered,  can  easily  be  determined  by 
heating  the  oil  until  vapors  are  given  off.  Retain  it  at  this  tem- 
perature for  about  20  minutes.  An  acid  treated  oil  will  turn  black, 
and  upon  standing  for  12  hours  will  show  a  black  precipitate 
showing  that  a  chemical  reaction  has  taken  place  and  that  there 
are  foreign  ingredients  in  the  oil.  A  filtered  oil  will  darken  in 
color  but  will  show  no  sediment. 

Emulsion  Test. — Take  35  cc.  of  the  oil  and  an  equal  amount 
of  water  (preferably  distilled  in  a  4-ounce  bottle).  Shake  the 
mixture  for  about  ^2  hour  and  allow  it  to  stand  for  a  day.  An 
acid  treated  oil  will  show  a  line  of  emulsion  between  the  oil  and 
the  water.  A  filtered  oil  will  separate  out  completely  showing 
that  there  are  no  foreign  ingredients  in  the  oil. 

As  all  mineral  motor  oils  are  composed  of  about  85  per  cent, 
carbon  and  15  per  cent,  hydrogen  a  carbonless  oil  is  impos- 
sible. What  is  meant  by  low  carbon  content  of  an  oil  is  the 
free  carbon.  Even  this  factor  never  reaches  zero,  and  can  be 
determined  by  distilling  (destructive  distillation)  a  given  amount 
of  the  oil  in  a  flask  and  weighing  after  evaporating  to  dryness. 
(Rate  of  distillation  i  drop  per  second.)  The  solid  matter  re- 
maining in  the  flask  is  the  percentage  of  carbon  residue. 
28 


434  Engine:ering  chemistry 

However,  if  the  conditions  are  not  favorable,  such  as  leaky  pis- 
ton rings,  etc.,  the  highest  quality  motor  oils  will  leave  an  excess 
deposit  of  carbon.  Generally  the  carbon  residue  of  motor  oils  is 
higher  in  the  heavier  bodied  oils. 

The  flash  point  of  motor  oils  is  important  only  from  the  stand- 
point of  disintegration.  Practically  all  oils,  disregarding  quality, 
are  destroyed  when  introduced  into  the  explosion  chamber  of 
the  cylinder,  due  to  the  high  degree  of  heat  therein.  But  the 
temperatures  of  the  various  parts  of  the  engine  when  in  opera- 
tion determine  the  loss  by  evaporation.  The  approximate  aver- 
age temperatures  of  the  various  parts  when  in  operation  are  as 
follows : 

Degrees 

Piston  heads  300  to  1,000 

Piston  walls  200  to  400 

Cylinder  walls    180  to  350 

Crank  bearings   140  to  250 

Oil  well  90  to  200 

Therefore  it  will  be  seen  that  an  oil  of  a  flash  below  400°  F. 
will  disintegrate  very  rapidly  and  will  require  very  frequent 
replenishing.  Also,  from  the  above  temperatures  it  will  be  seen 
that  the  cold  test  is  of  minor  importance  except  where  the  oil  is 
fed  through  exterior  piping. 

The  viscosity  of  motor  oils  is  the  most  important  factor  in 
lubrication.  If  the  viscosity  be  either  too  high  or  too  low  the 
friction  of  the  moving  parts  is  increased,  hence  loss  of  horse- 
power and  high  cost  of  operation. 

By  extensive  tests  it  has  been  proven  that  oils  between  180 
and  300  seconds  are  regarded  (Saybolt  Universal  Viscosimeter) 
as  meeting  the  general  scope  of  motor  lubrication  requirements, 
subdividing  the  above  into  the  standard  grades  as  regards  viscos- 
ity they  may  be  classified  as  follows : 

Light  body  for  high  speed  light  duty,  where  splash  system  of 
lubrication  is  used,  220  seconds  at  70°  F.  (Saybolt  universal 
viscosimeter). 

Medium  "body,  275  to  300  seconds  at  70°  F,    ( Saybolt  universal 
viscosimeter). 
(The  oil  will  answer  the  general  requirements  of  automobile  motors.) 


DNGINKKRING   CHEMISTRY  435 

The  oils  for  heavy  duty  slow  speed  engines  where  force  feed 
system  of  lubrication  is  used  should  have  a  viscosity  of  400  to 
450,  and  for  extra  heavy  oil  for  air-cooled  motors,  such  as  motor- 
cycles, etc.,  the  viscosity  should  be  about  100  seconds  at  212°  F. 

Transmission  oils  and  gear  compounds  should  be  semi-fluid. 
If  a  hard  grease  is  used  the  gears  cut  a  permanent  track  in  the 
grease  and  in  time  the  teeth  become  dry,  resulting  in  excessive 
friction. 

The  grease  should  be  a  compound  of  fiber  grease  and  a 
heavy  cylinder  stock.  The  cheaper  grades  of  greases  are  made 
by  compounding  heavy  oils  and  paraffine  wax.  This  is  a  poor 
lubricant. 

Internal  combustion  engines  should  not  use  as  much  oil  as 
steam  engines  as  the  cylinder  walls  are  dry.  The  conditions 
approach  that  of  superheated  steam  cylinders. 

A  steel  company  employing  De  La  Vergne's  oil  engines  as  a 
source  of  motive  power  mix  3/2  pound  of  finely  divided  graphite 
with  the  cylinder  oil  and  assert  that  it  materially  increases  the 
efficiency  of  the  engine. 

The  Analysis  of  Lubricating  Oils  Containing  Blown  Rape-Seed 
and  Blown  Cotton-Seed  Oils. 

Rape-seed  oil  has  long  been  the  standard  oil  in  Europe  for 
lubrication.  Its  constancy  of  viscosity  at  varying  temperatures, 
its  non-liability  to  acidity  as  compared  with  other  seed  oils,  and 
its  low  cold  test,  unite  in  producing  the  results  required  of  a 
good  lubricant.  It,  however,  is  no  exception  to  the  rule  that 
vegetable  and  animal  oils  suffer  partial  decomposition  when  sub- 
jected to  high  temperature  produced  by  friction,  with  the  result 
that  fatty  acids  are  liberated  and  corrosion  of  bearings  produced. 

The  substitution  of  mineral  oils  in  varying  proportions  with 
rape-seed  oil  has  reduced  this  tendency,  this  reduction  being 
determined  by  the  percentage  of  mineral  oil  present,  as  the  latter 
liberates  no  free  acids. 

It  is  a  peculiar  fact,  however,  that  a  mineral  oil  alone  does  not 
give  as   satisfactory   results   in   lubrication    (especially   cylinder 


436  ENGINEERING   CHEMISTRY 

lubrication^)  as  does  a  mixture  of  mineral  and  vegetable  or 
mineral  and  animal  oils,  one  of  the  primary  causes  being  that 
the  viscosity  of  mineral  oils  rapidly  diminishes  at  high  tempera- 
tures, v^hereas  the  reduction  of  viscosity  of  vegetable  and  animal 
oils  is  very  much  less. 

If  it  w^ere  not  for  this  peculiarity  between  these  two  classes  of 
oils,  mineral  lubricating  oils  could  easily  supplant  (on  the  score 
of  cheapness)  all  other  oils  used  in  lubrication. 

The  admixture  of  oils  then  being  required  for  the  better  class 
of  lubricants,  it  follows  that  in  England  where  rape-seed  oil  has 
been  the  standard,  its  use  should  be  continued  in  compounded 
oils. 

The  proportion  of  rape-seed  oil  added  to  mineral  oil  varies 
from  5  to  20  per  cent.  Where  the  mineral  oil  is  a  clear  paraffine 
oil  20  per  cent,  of  the  seed  oil  is  used ;  where  the  mineral  oil  is  a 
dark,  heavy  oil,  5  per  cent,  is  generally  added. 

The  separation  and  estimation  of  the  rape-seed  oil  in  these 
mixtures  presents  no  difficulty  to  the  analytical  chemist  when  no 
other  seed  oil  is  present,  since  the  saponification  of  the  seed  oil, 
the  separation  of  the  fatty  acids  and  recognition  of  the  same  are 
a  part  of  the  usual  chemical  work  of  this  character.  The  recog- 
nition of  the  constituents  of  a  mixed  lubricating  oil  by  analysis  is 
a  very  dififerent  problem  from  giving  a  formula  by  which  the 
mixture  can  be  made.    This  is  evidenced  as  follows : 

Suppose  the  analysis  shows — 

Per  cent. 

Rape-seed  oil   20 

Paraffine  oil  80 

Paraffine  oil  varies  in  specific  gravity  from  0.875  to  0.921,  and  it 
is  essential  to  include  in  the  report  of  the  analysis  not  only  the 
amount  of  paraffine  oil,  but  also  the  gravity,  since  paraffine  oil 
of  gravity  0.875  is  a  very  different  product  from  that  of  0.921 
gravity,  the  former  selling  at  7^  cents  and  the  latter  at  23  cents 
per  gallon.  This  determination  can  be  made  by  taking  the  gravity 
of  the  original  mixed  oil  (0.912),  then  knowing  by  the  analysis 

1  The  Railroad  and  Engineering  Journal  bA,  73-126. 


ENGINEERING    CHEMISTRY  437 

that  20  per  cent,  is  rape-seed  oil  (gravity  0.918),  the  gravity  of 
the  80  per  cent,  of  paraffine  oil  is  easily  calculated.    Thus : 

X  =  specific  gravity  of  rape-seed  oil   (0.918), 
y  ^=  specific  gravity  of  paraffine  oil. 
Then 

i-^  +  ^y  =  o.gi2, 

0.183  +  ^y  ~  0-912, 
1^  =  0.729, 

_>^  :^  0.910. 

The  mixture  being  composed,  therefore,  of — 

Per  cent. 

Paraffine  oil    (specific  gravity  0.910) 80 

Rape-seed  oil    (specific  gravity  0.918) 20 

The  direct  determination  by  analysis  from  the  ether  solution 
of  the  mineral  oil  in  the  mixture  does  not  give  an  oil  of  the  same 
specific  gravity  as  the  mineral  had  before  it  was  mixed  with  the 
seed  oil.  This  can  be  accounted  for  by  the  volatilization  of  a 
portion  of  the  lighter  hydrocarbons  of  the  mineral  oil  when  the 
ether  is  expelled  during  the  analysis.  For  this  reason  the  deter- 
mination of  the  percentage  of  seed  oil  and  the  calculation  of  the 
mineral  oil  offers  less  liability  to  failure  than  finding  the  mineral 
oil  directly. 

The  introduction  of  blown  rape-seed  oil  instead  of  the  normal 
rape-seed  oil  complicates  the  investigation  and  renders  the  use 
of  the  formula  above  given  valueless.  Rape-seed  oil  has  a 
gravity  of  0.915  to  0.920.  Rape-seed  oil  blown  has  a  gravity  of 
from  0.930  to  0.960. 

Two  difficulties  are  immediately  presented  :  ( i )  The  chemical 
analysis  does  not  indicate  whether  the  rape-seed  oil  is  blown  or 
not;  (2)  The  use  of  the  formula  given  without  the  correct 
gravity  of  the  blown  oil  would  give  false  results  regarding  the 
paraffine  oil.  To  overcome  this  difficulty  some  synthetical  work 
is  required. 

Suppose  the  specific  gravity  of  the  mixed  oil  is  0.922  and  the 
analysis  shows  20  per  cent,  of  rape-seed  oil.  It  will  be  necessary 
then  to  produce  a  mixture  in  these  proportions  that  will  duplicate 
the  original  sample.     A  check  upon  this  will  be  the  viscosity  of 


438  DNGINDDRING   CHEMISTRY 

the  original  sample  as  compared  with  the  one  to  be  made  by 
formula.     Thus : 

The  original  oil  has  a  gravity  of  0.922,  contains  (by  analysis) 
20  per  cent,  of  rape-seed  oil,  and  has  a  viscosity  at  100°  F.  of 
335  seconds  (Pennsylvania  Railroad  pipette). 

First. — Make  a  mixture  of  paraffine  oil  (specific  gravity  0.910) 
generally  used  in  this  character  of  lubricant,  80  per  cent.,  and 
rape-seed  oil  (unblown),  20  per  cent.  The  viscosity  is  165  sec- 
onds, showing  that  this  mixture  cannot  be  used  in  place  of  the 
original  oil. 

Second. — Make  a  mixture  of  paraffine  oil  (specific  gravity 
0.910)  and  rape-seed  oil  partially  blown  (specific  gravity  0.930), 
in  the  same  proportions  as  above.  The  resulting  viscosity  is  267 
seconds,  showing  that  the  compound  is  still  lacking  in  viscosity. 

Third. — Make  a  mixture  of  paraffine  oil  (specific  gravity 
0.910),  80  parts,  and  rape-seed  oil,  blown  (specific  gravity  0.969), 
20  parts ;  the  viscosity  is  332  seconds. 

This  now  fulfils  the  conditions  required  and  the  synthetical 
sample  agrees  with  the  original  in  gravity,  composition,  and 
viscosity. 

The  use  of  blown  rape-seed  oil  is  being  gradually  replaced  by 
blown  cotton-seed  oil.  The  latter,  which  has  had  but  a  limited 
use  in  lubrication,  owing  to  its  liability  to  acidity,  has  been 
greatly  improved  by  this  process  of  "blowing,"  which  is  nearly 
complete  oxidation  of  the  oil  under  comparatively  high  tem- 
perature. 

This  largely  prevents  the  occurrence  of  the  acidity  in  the  oil, 
and  thus  the  main  objection  to  its  use  in  lubrication  disappears. 
It  is  much  cheaper  than  rape-seed  oil,  since  it  costs  30  cents  per 
gallon,  to  60  cents  per  gallon  for  the  latter.  The  chemical  re- 
actions of  the  two  oils  are  very  similar,  and  careful  analytical 
work  is  required  that  the  chemist  be  not  misled. 

The  following  table  of  comparisons  will  indicate  this : 

Specific  Gravity. 

Cotton-seed  oil    0.920  to  0.925 

Rape-seed  oil  0.915  to  0.920 

Blown  cotton-seed  oil    0.930  to  0.960 

Blown  rape-seed  oil    0.930  to  0.960 


i^NGlNKERING    CHEMISTRY  439 

Viscosity  (Pennsylvania  Railroad  Pipette)  at  100°  F. 

Seconds 

Cotton-seed  oil   (specific  gravity  0.925) 162 

Rape-seed  oil  (specific  gravity  0.918) 210 

Blown  cotton-seed  oil  (specific  gravity  0.960) 2,143 

Blown  rape-seed  oil  (specific  gravity  0.960) 2,160 

Heidenreich's  Test. 

Before  stirring  After  stirring 

Cotton-seed  oil  Faint  reddish  brown        Brown 

Rape-seed  oil  Yellow-brown  Brown 

Massie's  Test. 

Cotton-seed  oil   ...   Orange-red 

Rape-seed  oil   Orange 

Iodine  Absorption. 

Cotton-seed  oil   104  to  114 

Blown  cotton-seed  oil   93  to  103 

Rape-seed  oil  102  to  108 

Blown  rape-seed  oil   94  to  100 

In  the  comparison  of  the  tw^o  oils,  when  not  mixed  with  a  min- 
eral oil,  the  above  tests  can  be  used.  The  conditions  are  altered, 
however,  when  either  one  or  both  are  so  mixed,  since  these  tests 
apply  only  to  the  pure  oils  and  not  to  those  reduced  with  large 
percentages  of  mineral  oil.  After  the  separation  of  the  seed  oil 
from  the  mineral  oil  by  saponification  the  identification  of  the 
seed  oil  depends  upon  the  reactions  of  the  fatty  acids  obtained, 
and  a  careful  examination  and  comparison  of  these  reactions 
shows  that  the  melting  points  have  the  greatest  difference  and 
thus  become  a  means  of  recognition. 

Thus,  the  fatty  acids  from  rape-seed  oil  melt  at  20°  C,  and 
from  cotton-seed  oil  at  30°  C.  Hence,  if  upon  analysis  of  a 
lubricating  oil  under  above  conditions,  the  fatty  acids  obtained 
show  a  melting-point  of  20°  C.  the  seed  oil  can  be  pronounced 
rape-seed  oil. 

If  the  melting-point  is  between  these  limits,  say  23°  C,  the 
seed  oils  are  present  in  a  mixture,  the  proportions  of  which  can 
be  determined  by  the  following  formula : 


440  ENGINEERING   CHEMISTRY 

Wi  =  proportion  of  rape-seed  oil, 

W2  =  proportion  of  cotton-seed  oil, 

Ws  =  weight  of  mixture  (20  per  cent.), 
h  =  temperature  of  melting-point  of  fatty  acids  of  rape-seed  oil, 
fi  =  temperature  of  melting-point  of  fatty  acids  of  cotton-seed  oil, 
t:i  =:  temperature  of  melting-point  of  mixed  fatty  acids. 
Then 

4  —  4 

h        h 

L  —L 

w-i  =  '^4 r 

H  —  H 

Inserting  the  value : 

2X  —  ^o 

w.  =  20-^^ —  =  14  per  cent. 

'  20  —  30  ^ 

2X  —  20 

w.y  =  20  -^ =  6  per  cent. 

^  30  —  20  ^ 

Or, 

Per  cent. 

Paraffine  oil  80 

Rape-seed  oil   14 

Cotton-seed  oil   6 

Total   100 

By  synthetical  work  upon  these  proportions,  with  comparison 
of  viscosities  of  the  sample  submitted  with  the  product,  the 
result  will  be  not  only  a  correct  analysis  but  a  working  formula 
can  be  given  by  which  a  manufacturer  can  duplicate  the  original 
oil. 

Rapid  Determination  of  Fatty  Oil  Mixtures  with  Mineral 
Lubricating  Oils. 
In  the  presence  of  large  quantities  of  mineral  oil,  saponifica- 
tion with  alcoholic  potash  takes  a  long  time,  since  the  mineral 
oil  prevents  the  potash  coming  in  contact  with  the  fatty  oil. 
Schreiber's  method^  gives  good  results  in  a  short  time.  Weigh 
5  grams  of  the  oil  in  a  200  cc.  Erlenmeyer  flask,  add  25  to  50  cc. 
of  half-normal  alcoholic  potash  and  sufficient  benzol  (CyHj.)  to 
dissolve  the  oil  when  warmed  (generally  25  cc.  is  enough,  but 
with  heavy  cylinder  oils  as  much  as  50  cc.  may  be  necessary;  in 
this  case  it  is  well  to  add  25  cc.  of  neutral  alcohol).    Connect  the 

ly  Am.  Chem.  Soc,  1907,  29,  74. 


e;ngine:e:ring  chemistry  441 

flask  with  a  3-foot  condenser  and  set  it  on  the  iron  plate  that 
forms  the  top  of  the  steam  bath,  so  that  the  steam  will  not  strike 
it  directly,  and  regulate  the  seat  so  that  the  condensing  liquid  will 
not  be  forced  to  the  top  of  the  condenser.  In  this  way  the  con- 
tents of  the  flask  can  be  boiled  without  apparently  losing  any  of 
the  solvent.  Boil  for  30  minutes.  Cool,  add  phenolphthalein,  and 
titrate  the  excess  of  potassium  hydroxide  with  half-normal  sul- 
phuric acid.  On  adding  the  acid  the  liquid  separates  into  two 
layers  and  the  change  in  color  can  be  seen  in  the  lower  layer; 
the  titrating,  however,  must  be  conducted  slowly.  Subtract  the 
cubic  centimeters  of  sulphuric  acid  from  the  amount  used  on 
blanks  and  calculate  the  saponification  number.  For  all  prac- 
tical purposes  195  may  be  considered  as  the  saponification  number 
of  the  fatty  oils  used  in  lubricating  oils,  hence  if  S  equals  the 
determined  saponification  number,  100  S  divided  by  195  equals 
the  percentage  of  fatty  oil  present. 


OIL  USED  FOR  ILLUMINATION. 

Oil  used  for  illumination  may  be  classified  into  two  groups : 

1.  Refined  products  from  petroleum,  such  as  naphtha,  gaso- 
lene, kerosene,  signal  oil,  etc. 

2.  Certain  refined  oils  of  vegetable  and  animal  origin,  as  colza 
oil,  rape  oil,  lard  oil,  sperm  oil,  etc. 

Refined  Products  fpom  Petroleum. 

Kerosene  is  the  refined  product  from  petroleum  that  distills 
over  (in  the  refining  process)  after  the  lighter  oils,  naphthas,  etc., 
have  been  separated,  and  is  the  principal  oil  in  use  for  illumina- 
tion. In  color  it  varies  from  standard  white  to  water-white 
(colorless),  and  its  commercial  value  is  dependent  upon  its  flash- 
ing and  burning-point.  In  the  oil  trade,  the  burning  or  fire  tests 
are  classified  as  110°  F.,  120°  F.,  150°  F.,  and  300°  F. 

The  150°  F.  is  known  as  headlight  oil  and  the  300°  F.  as  min- 
eral sperm  and  mineral  colza. 

The  requirements  for  mineral  oils  to  be  used  in  railroad  illu- 
mination are  as  follows : 


442  ENGINEERING   CHEMISTRY 

Specifications  for  Petroleum  Burning  Oils. 
(Conditions  of  Shipment  and  General  Specifications.) 

This  material  will  be  purchased  by  weight.  Barrels  must  be  in  a  good 
condition  and  must  have  the  name  of  the  contents  and  the  consignee's 
name  and  address  on  each  barrel,  and  plainly  marked  with  the  gross  and 
net  weight  which  will  be  subject  to  the  company's  weight. 

When  received  all  shipments  will  be  promptly  weighed.  If  not  prac- 
ticable to  empty  all  the  barrels,  lo  per  cent,  will  be  emptied,  and  the  losses 
of  the  whole  shipment  will  be  adjusted  in  accordance  with  the  lo  per  cent, 
taken.  Should  the  net  weight  thus  obtained  be  less  by  i  per  cent,  than 
the  amount  charged  in  the  bill,  a  reduction  will  be  made  for  all  over 
I  per  cent. 

Prices  should  be  given  in  cents  or  hundredths  of  a  cent  per  pound. 

Shipments,  one  or  more  barrels  of  which  are  filled  with  oil  cloudy 
from  the  presence  of  glue,  or  which  contain  dirt,  water,  or  other  impuri- 
ties, will  be  rejected. 

Two  kinds  of  petroleum  burning  oils  will  be  used,  known  as  the  150° 
fire  test  for  general  use,  and  300°  fire  test  for  use  in  passenger  cars. 

Detaii,  Specifications. 
130°  Fire  Test  Oil. 
This  oil  must  conform  to  the  following  requirements : 

1.  It  must  have  a  flash  test  above  125°  F, 

2.  It  must  have  a  fire  test  not  below  150°  F. 

3.  It  must  have  a  cloud  test  not  above  0°  F. 

4.  It  must  be  a  "water  white"  in  color. 

5.  Its  gravity  must  be  between  44°  and  48°  B.  at  60°  F. 

300°  Fire  Test  Oil. 
This  oil  must  conform  to  the  following  requirements : 

1.  It  must  have  a  flash  test  above  250°  F. 

2.  It  must  have  a  fire  test  not  below  300°  F. 

3.  It  must  have  a  cloud  test  not  above  32°  F, 

4.  It  must  be  a  "standard  white"  in  color. 

5.  Its  gravity  must  be  between  38°  and  42°  B.  at  60°  F. 

Flash  Test.  Fire  Test. — The  requirements  for  the  flash  and 
fire  test  for  illuminating  oils  used  for  domestic  purposes  are  not 
so  rigid  as  for  railroad  practice.  In  fact  large  quantities  of  oil, 
flashing  below  110°  F.,  are  used,  the  cheaper  price  being  the 
incentive.  So  dangerous  are  these  oils  v^ith  low^  flash-points,  that 
many  states  have  passed  stringent  law^s  against  their  use.  An  oil 
with  a  fire  test  of  110°  F.  very  often  has  a  flash  test  of  90°  F.  .and 


ENGINKEJRING    CHEJMTSTRY 


443 


many  oils  with  a  fire  test  of  120°  F.,  flash  at  or  below  100°  F. 
It  is  the  flashing-point  of  an  oil  that  makes  it  dangerous  and 
while  the  refiners  of  oil  mark  their  products  by  the  fire  test  the 
laws,  as  passed  by  many  of  the  states,  specify  the  flash  test  as 
the  requisite. 

Cloud  Test. — The  cloud  test  is  made  as  follows :  Two  ounces 
of  the  oil  are  placed  in  a  4-ounce  sample  bottle,  with  a  thermom- 
eter suspended  in  the  oil.  The  bottle  is  exposed  to  a  freezing 
mixture  of  ice  and  salt  and  the  oil  stirred  with  the  thermometer 
while  cooling.  The  temperature  at  which  the  cloud  forms  is 
taken  as  the  cloud  test. 

The  instrument  that  gives  good  satisfaction  in  testing  illumi- 


Fig.   87. 


nating  oils,  not  lubricating  oils,  for  the  flash  and  fire  test  is  called 
the  Wisconsin  Tester  (Fig.  87).     It  is  thus  described: 


444  ENGINEEJRING   CHEMISTRY 

(i)  On  the  left  side  of  figure  is  shown  the  instrument  entire.  It  con- 
sists of  a  sheet-copper  stand  8^  inches  high,  exclusive  of  the  base,  and 
4^^  inches  in  diameter.  On  one  side  is  an  aperture  3^  inches  high,  for 
introducing  a  small  spirit  lamp.  A,  about  3  inches  in  height,  or  better,  a 
small  gas  burner  in  place  of  the  lamp  when  a  supply  of  gas  is  at  hand. 
The  water  bath,  D,  is  also  of  copper,  and  is  4%  inches  in  height  and 
4  inches  inside  diameter.  The  opening  in  the  top  is  2%  inches  in  diameter. 
It  is  also  provided  with  a  j4-inch  flange  which  supports  the  bath  in  the 
cylindrical  stand.  The  capacity  of  the  bath  is  about  20  fluid  ounces,  this 
quantity  being  indicated  by  a  mark  on  the  inside.  C  represents  the  copper 
oil  holder.  The  lower  section  is  3)^  inches  high  and  2^  inches  inside 
diameter.  The  upper  part  is  i  inch  high  and  3^  inches  in  diameter,  and 
serves  as  a  vapor  chamber.  The  upper  rim  is  provided  with  a  small  flange 
which  serves  to  hold  the  glass  cover  in  place.  The  oil  holder  contains 
about  10  fluid  ounces,  when  filled  to  within  J^  inch  of  the  flange  which 
joins  the  oil  cup  and  the  vapor  chambers.  In  order  to  prevent  reflection 
from  the  otherwise  bright  surface  of  the  metal,  the  oil  cup  is  blackened 
on  the  inside  by  forming  a  sulphide  of  copper,  by  means  of  sulphide  of 
ammonium. 

The  cover,  C,  is  of  glass,  and  is  35^  inches  in  diameter ;  on  one  side 
is  a  circular  opening,  closed  by  a  cork  through  which  the  thermometer,  B, 
passes.  In  front  of  this  is  a  second  opening  ^  inch  deep  and  the  same 
in  width  on  the  rim,  through  which  the  flashing  jet  is  passed  in  testing. 
The  substitution  of  a  glass  for  a  metal  cover  more  readily  enables  the 
operator  to  note  the  exact  point  at  which  the  flash  occurs.  A  small  gas 
jet,  j4  inch"  in  length,  furnishes  the  best  means  for  igniting  the  vapor. 
Where  gas  cannot  be  had  the  flame  from  a  small  waxed  twine  answers 
very  well. 

(2)   The  test  shall  be  applied  according  to  the  following  directions: 

Remove  the  oil  cup  and  fill  the  water  bath  with  cold  water  up  to  the 
mark  on  the  inside.  Replace  the  oil  cup  and  pour  in  enough  oil  to  fill  it 
to  within  %  inch  of  the  flange  joining  the  cup  and  the  vapor  chamber 
above.  Care  must  be  taken  that  the  oil  does  not  flow  over  the  flange. 
Remove  all  air  bubbles  with  a  piece  of  dry  paper.  Place  the  glass  cover 
on  the  oil  cup,  and  so  adjust  the  thermometer  that  its  bulb  shall  be  just 
covered  by  the  oil. 

If  an  alcohol  lamp  is  employed  for  heating  the  water  tub,  the  wick 
should  be  carefully  trimmed  and  adjusted  to  a  small  flame.  A  small 
Bunsen  burner  may  be  used  in  the  place  of  the  lamp.  The  rate  of  heating 
should  be  about  2°  per  minute,  and  in  no  case  exceed  3°. 

As  a  flash  torch,  a  small  gas  jet,  ^  inch  in  length,  should  be  employed. 
When  gas  is  not  at  hand,  employ  a  piece  of  waxed  linen  twice.  The 
flame  in  this  case,  however,  should  be  small. 

When   the   temperature   of   the   oil   has    reached   85°    F.,   the   testings 


DNGINEERING    CHE:mISTRY  445 

should  commence.  To  this  end  insert  the  torch  into  the  opening  in  the 
cover,  passing  it  in  at  such  an  angle  as  to  well  clear  the  cover,  and  to  a 
distance  about  half  way  between  the  oil  and  the  cover.  The  motion  should 
be  steady  and  uniform,  rapid  and  without  any  pause.  This  should  be 
repeated  at  every  2°  rise  of  the  thermometer  until  the  temperature  has 
reached  95°,  when  the  lamp  should  be  removed  and  the  testings  should  be 
made  for  each  degree  of  temperature  until  100°  is  reached.  After  this 
the  lamp  may  be  replaced,  if  necessary,  and  the  testings  continued  for 
each  2°. 

The  appearance  of  a  slight  bluish  flame  shows  that  the  flashing  point 
has  been  reached. 

In  every  case  note  the  temperature  of  the  oil  before  introducing  the 
torch.    The  flame  of  the  torch  must  not  come  in  contact  with  the  oil. 

The  water  bath  should  be  filled  with  cold  water  for  each  separate  test, 
and  the  oil  from  a  previous  test  carefully  wiped  from  the  oil  cup. 

(3)  The  instrument  to  be  used  in  testing  oils  which  come  under  the 
provisions  of  Section  2  of  the  law  shall  consist  of  the  cylinder,  D,  and  the 
copper  oil  cup,  C,  together  with  a  copper  collar  for  suspending  the  cup 
in  the  cylinder,  and  an  adjustable  support  for  holding  the  thermometer. 

(4)  The  test  for  ascertaining  the  igniting  point  shall  be  conducted  as 
follows :  Fill  the  cup  with  the  oil  to  be  tested  to  within  ^  inch  of  the 
flange  joining  the  cup  and  the  vapor  chamber  above.  Care  must  be  taken 
that  the  oil  does  not  flow  over  the  flange.  Place  the  cup  in  the  cylinder 
and  adjust  the  thermometer  so  that  its  bulb  shall  be  just  covered  by  the 
oil.  Place  the  lamp  or  gas  burner  under  the  oil  cup.  The  rate  of  heating 
should  not  exceed  10°  a  minute  below  250°  F.,  nor  exceed  5°  a  minute 
above  this  point.  The  testing  flame  described  in  the  directions  for  ascer- 
taining the  flashing  point  should  be  used.  It  should  be  applied  to  the  sur- 
face of  the  oil  at  every  5°  rise  in  the  thermometer,  till  the  oil  ignites. 

There  are  various  forms  of  flash  and  fire  testing  apparatus  for 
illuminating  oils,  and  as  some  are  standard  in  certain  states,  a 
few  will  be  described. 

Dire:ctions  for  Using  the  Tagliabue:  Opkn  Te:stkr. 
(Fig.  88.) 

The  instrument  should  stand  level.  Partially  fill  the  metal  bath 
cup  with  water,  leaving  room  for  displacement  by  the  glass  oil 
cup,  which  then  place  in  the  bath.  Fill  the  glass  oil  cup  with  the 
oil  to  be  tested  to  within  y%  inch  of  its  upper  level  edge.  See 
that  there  is  no  oil  on  the  outside  of  the  cup,  or  upon  its  upper 
level  edge,  using  filter  paper  to  clean  with  in  preference  to  cotton 
or  woolen  material.     Adjust  the  horizontal  flashing- taper-guide- 


446 


EJNGINEKRING   CHEMISTRY 


^^^^  ^jmgi 


ENGINEEJRING   CHEMISTRY  447 

wire  in  place.  Suspend  the  thermometer,  with  the  bulb  of  same 
well  covered  by  the  oil.  Heat  bath  with  small  flame  lamp — alco- 
hol, gas  or  other — having  the  flame  so  adjusted  that  it  will  raise 
the  temperature  of  the  oil  not  faster  than  2^  per  minute,  without 
removing  the  lamp  during  the  whole  operation.  Remove  air 
bubbles,  if  any,  from  the  surface  of  the  oil  before  first  trial  for 
flash  is  made. 

At  the  proper  trial  temperatures  noted  below,  try  for  flash 
with  a  small  (not  over  ^  inch)  bead  of  flame  on  the  end  of  a 
piece  of  lighted  twine,  or  an  equivalent  sized  gas  jet;  by  drawing 
it  quickly  and  without  pause  across  the  guide-wire  from  left  to 
right. 

Triai,  Temperature  Tabee. 


For  oils  ex- 
pected to 
have  a  fire 
test  c^ 

Try  for  flash 

hirst 

at 

Then  at 

110° 

F. 

8? 

F. 

90° 

95° 

ICX)° 

105° 

108° 

1 10^ 

115° 

90° 

95° 

100° 

105° 

110° 

113° 

115' 

120° 

95° 

100° 

105° 

110° 

115° 

118° 

120' 

125° 

100° 

105° 

110° 

115° 

120° 

123° 

125' 

130° 

100° 

105° 

110° 

115° 

120° 

125° 

130= 

135° 

105° 

110° 

115° 

120° 

125° 

130° 

135' 

140° 

110° 

115° 

120° 

125° 

130° 

135° 

140' 

145° 

115° 

120° 

125° 

130° 

135° 

140° 

145' 

150° 

120° 

125° 

130° 

135° 

140° 

145° 

150' 

As  the  Tagliabue  Closed  Tester  for  Illuminating  Oils  (Fig.  89) 
is  similar  in  construction  to  the  Foster  instrument  for  the  same 
purpose,  except  the  latter  has  an  automatic  flash  extinguisher,  a 
description  of  the  Foster  is  given. 

The  instrument  consists  of  a  copper  lamp  furnace  containing 
a  water  bath  and  oil  cup;  the  latter  surmounted  by  a  closed 
vapor  chamber,  which  is  pierced  at  two  points  symmetrically 
placed  for  the  reception  of  a  thermometer  and  a  flashing  lamp  or 
taper;  the  apparatus  being  elliptical  in  shape,  the  thermometer  is 
placed  in  one  focus  of  the  ellipse  and  the  flashing  taper  in  the 
other.  The  flashing  taper  consists  of  a  small  cylindrical  wick 
holder,  supported  by  radical  arms  to  an  annular  ring,  and  rests 
upon  a  similar  ring  at  the  bottom  of  an  open,  shallow  basin — the 


44^  ENGINEERING    CHEMISTRY 

Spaces  between  the  radical  arms  giving  egress  to  the  oil  vapor, 
w^hile  the  v^ack  itself  extends  down  into  the  body  of  the  oil  within 
the  cup.  An  inverted  conical  thimble,  resting  upon  the  rim  of 
the  basin,  prevents  the  dissipation  of  the  vapor.  The  thermom- 
eter is  mounted  in  a  copper  tube  cut  away  in  front  to  expose  the 
scale,  the  bulb  of  the  thermometer,  when  in  position,  being  within 
the  body  of  the  oil  at  a  definite  distance  below  the  surface.  An 
orifice  around  the  tube  of  the  thermometer,  definite  in  diameter 
and  distance  above  the  surface  of  the  oil,  allows  a  downward 
current  of  atmospheric  air  when  the  flashing  taper  is  alight. 

An  index  is  placed  within  the  water  bath  and  within  the  oil 
cup  for  maintaining  uniformity  in  the  filling  of  each. 

The  heating  lamp  of 'the  lamp  furnace  has  its  wick  adjustable 
to  facilitate  uniformity  in  the  rate  of  heating. 

Directions  for  Using  the  Foster  Automatic 
On.  Tester.    (Fig.  90.) 

1.  Remove  the  thermometer  with  its  mounting  from  the  oil  cup. 

2.  Lift  off  the  oil  cup  containing  the  flashing  taper,  and  fill  the 
open  water  bath  with  water  half  full. 

3.  Now  take  out  the  wick  holder  from  the  oil  cup,  and  fill  this 
vessel  with  the  oil  to  be  tested — pouring  in  the  oil  at  the  place 
of  the  wick  holder  and  noting  the  gauge  mark  at  the  thermometer 
hole — pour  in  the  oil  very  gradually  as  the  surface  approaches 
the  gauge  mark.  The  gauge  mark  consists  of  a  small  pendant 
shelf,  and  the  oil  cup  is  properly  filled  when  the  upper  surface 
of  the  oil  just  adheres  to  the  lower  surface  of  the  gauge  mark. 
Too  much  care  cannot  be  taken  at  this  point;  therefore,  having 
ceased  pouring,  tip  the  cup  so  that  the  oil  flows  away  from  the 
gauge;  and  then  gradvially  restoring  it  to  the  horizontal,  see  that 
the  surface  again  adheres,  and  add  a  little  more  oil  if  it  does  not. 

4.  See  that  the  wick  of  the  flashing  taper  be  adjusted  to  give 
a  very  small  flame — a  flame  that  does  not  exceed  ^  inch  in 
height.  A  flame  that  exhibits  as  much  blue  at  its  base  as  yellow 
at  its  top  is  right. 

5.  Now  set  the  oil  cup  on  top  and  into  the  water  bath ;  return 
the  flashing  taper  to  its  place,  inverting  the  conical  thimble  around 


e:nginke)ring  chemistry 


449 


it,  and  return  the  thermometer  to  its  place  upon  the  cup;  in 
doing  this  be  sure  that  the  casing  of  the  latter  is  pushed  down 
upon  the  cup  as  far  as  it  will  go. 

6.  Fill  the  lamp  beneath  half  full  of  alcohol,  light  it  and  put 
it  in  its  place  beneath  the  water  bath.  No  wnote  the  rate  of 
increase  in  temperature  as  shown  by  the  thermometer,  and  adjust 


Fig.  91 


the  wick  to  raise  the  temperature  at  the  rate  of  2°  per  minute. 
When  the  temperature  has  reached  90°,  light  the  flashing  taper 
and  observe  it  closely.  As  soon  as  the  oil  under  test  has  reached 
its  ''flashing  point"  the  flame  of  this  taper  will  be  extinguished 
by  the  "flash,"  and  the  point  of  attention  is  to  note  the  tempera- 
ture at  the  instant  the  flame  of  the  taper  is  extinguished.  This 
29 


450- 


KNGINEKRING   CHEMISTRY 


"flashing  point"  is  the  point  of  temperature  at  which  the  oil 
generates  a  vapor  and  indicates  that  this  has  formed  an  explosive 
mixture  with  atmospheric  air. 

The  instrument  for  determining  the  flash  and  fire  test  of  illumi- 
nating oils  used  by  the  chemists  of  the  Standard  Oil  Co.  is  the 
Saybolt  Electric  Tester,  Fig.  91. 


Requirements  oe  Various  States  Regarding  the  Flash  and 

Fire  Test  oe  Illuminating  Oils.^ 

state  Flash  pt.  °F.        Fire,  °F.  Instrument 

Arkansas   130°  Tagliabtie   (closed) 

Columbia,  District  of..  120°  

Connecticut 110°  140°  Tagliabue  (open  cup) 

Florida  130°  Tagliabue   (closed) 

Georgia   120° 

Illinois    150"  Tagliabue    (closed) 

Indiana    120°  Indiana 

Iowa   105°  "Closed  Test" 

Kansas   110°  110°  Tagliabue    (closed) 

Kentucky  130° 

Louisiana    125°  Tagliabue   (closed) 

Maine   120°  Tagliabue  (open) 

Maryland    110°  Tagliabue   (closed) 

Massachusetts  110°  Tagliabue  (open) 

Michigan   120°  148°  Foster  (closed) 

Minnesota   110°  Minnesota 

Missouri    ...'. 150°  Tagliabue    (closed) 

Montana  1 10°  

Nebraska  100°  Foster  (closed) 

New  Hampshire 100°  120°  Tagliabue   (closed) 

New  Jersey 100°  "Closed  Tester" 

New  Mexico 150° 

New  York 110°  Tagliabue   (closed) 

North  Carolina 100°  Foster  (closed) 

North  Dakota  100°  

Ohio    120°  Foster  (closed) 

Pennsylvania No  law  or  requirement 

Rhode  Island  110°  Tagliabue   (closed) 

South  Dakota  110°  Foster  (closed) 

Tennessee    120°  TagHabue  (open) 

Vermont  110°  Tagliabue   (closed) 

Wisconsin    120°  "Wisconsin"   (closed) 

^Gill:    Oil  Analysis   (with  addition  by  author). 


EJNGINEERING   CHEMISTRY  45 1 

Specifications  for  ''Mineral  Sperm  Oil"  (Illuminating  Oil). 
Issued  by  the  Navy  Department,  June  15,  1910. 

Superseding  Specifications  24-O-2,  issued  June,  1902; 
April,  1905,  and  April  8,  1908. 

Must  be  prime  white  or  better  and  free  from  all  cloudiness,  impuri- 
ties, or  adulterations ;  must  not  become  cloudy  at  any  temperature  above 
32°  F. ;  must  be  entirely  free  from  acid;  must  not  flash  below  255°  F. 
(open  tester),  300°  F.  fire  test,  and  have  a  specific  gravity  between  37° 
and  41°  B.  (0.8383  to  0.8187)  at  60°  F. ;  Lima  oil  products  excluded;  to 
be  purchased  and  inspected  by  weight. 

Inspection  and  Deuvery. 

1.  Before  acceptance  the  oil  will  be  inspected.  Samples  of  each  lot 
will  be  taken  at  random,  the  samples  well  mixed  together  in  a  clean 
vessel,  and  the  sample  for  test  taken  from  this  mixture.  Should  the 
mixture  be  found  to  contain  any  impurities  or  adulterations,  the  whole 
delivery  of  oil  it  represents  will  be  rejected,  and  is  to  be  removed  by  the 
contractor  at  his  own  expense. 

2.  The  quantity  delivered  to  be  determined  by  weight ;  the  number 
of  pounds  per  gallon  to  be  determined  by  the  specific  gravity  of  the  oil 
at  60°  F.  multiplied  by  8.33  pounds,  the  weight  of  a  gallon  (231  cubic 
inches)  of  distilled  water  at  the  same  temperature. 

1.  Determination  of  the  Color  of  Kerosenes. 

The  grades  of  color  of  an  oil  are  noted  as  standard  white, 
prime  white,  superfine  white  and  water  white,^  and  the  instrument 
generally  used  for  determination  of  the  color  in  oils  is  the 
Stammer  colorimeter  (Fig.  92).  Tube  I  is  closed  at  the  bottom 
by  a  transparent  glass  plate,  is  open  at  the  top,  and  a  project- 
ing lip  on  the  side  whereby  the  oil  to  be  tested  can  be  poured  in 
or  out.  The  tube  is  fastened  to  the  stand  by  two  screws.  The 
measuring  tube  III  is  closed  at  the  bottom  by  a  colorless  glass 
plate  and  is  movable  inside  of  tube  I. 

The  color  glass  tube  II  which  is  joined  firmly  to  the  measuring 
tube  III  is  open  at  the  bottom  and  at  the  top  contains  a  colored 
glass  plate,  which  plate  can  be  substituted  with  other  tinted  glass 
plates.  The  movement  of  the  joined  tubes  II  and  III  is  produced 
by  enclosed  ratchet  work,  the  movement  of  the  tubes  being  read 
on  a  scale  on  the  back  of  the  stand,  and  stated  in  millimeters. 

^  In  Bremen,  the  varieties  are  rated  as  water  white,  prime  white,  standard  white, 
prime  light  straw,  light  straw  and  straw. 


452 


ENGINEERING    CHEMISTRY 


Since  the  color  of  a  liquid  is  inversely  proportional  to  the  height 
of  the  column,  which  is  necessary  to  give  the  standard  color,  and 
since  this  color  is  here  expressed  by  lOO,  the  absolute  number 
for  expressing  the  tone  of  color  of  any  oil  is  obtained  by  dividing 


Fig    92. 

this  100  by  the  number  of  millimeters  read  off  from  the  scale. 
For  example : 

Millimeter  scale  Color 

1       100.00 

2       50.00 

7     1429 

19       5.26 

The  color,  tone,  and  thickness  of  the  standard  glass  is  so 
chosen  that  the  scale  shows  the  following  values  for  the  ordinary 
brands  of  illuminating  oils : 

Millimeters 

Standard  white    50.00 

Prime  white   86.50 

Superfine  white   199-50 

Water  white   300.00 


ENGINEERING   CHEMISTRY  453 

Wilson's  colorimeter,  largely  used  in  England,  is  very  similar 
in  construction  to  the  Stammer.^ 

2.    Vegetable  and  Animal  Oils. 

The  two  principal  oils  of  this  class  in  use  for  illumination  are 
colza  and  lard  oil. 

In  this  country  the  former  has  never  been  used  to  any  great 
extent,  its  use  being  confined  principally  to  Europe,  but  lard  oil 
and  sperm  oil,  in  former  years,  before  the  introduction  of  the 
petroleum  products  for  this  purpose,  were  largely  used  as  illumi- 
nants.  Except  in  railroad  practice  and  then  in  yearly  decreasing 
amounts  their  use  now  is  very  limited  in  this  direction.  In  the 
matter  of  illumination,  the  methods  made  use  of  by  the  railroads 
are  worthy  of  study  and  comparison,  and  it  is,  in  a  great  measure, 
due  to  the  investigations  carried  out  in  their  interests  that  the 
great  advances  in  this  direction  are  due. 


LINSEED  OILS. 


The  Principal  Chemical  Tests. 

Specific  Gravity. — The  specific  gravity  of  pure  linseed  oil,  with- 
out driers,  at  60°  F.,  is  0.932,  which  equals  20°  of  the  Baume 
hydrometer;  that  of  boiled  oil  is  0.941,  which  equals  19°  B.  The 
addition  of  25  per  cent,  of  cotton-seed  oil  reduces  the  Baume 
hydrometer  1°  and  the  addition  of  10  per  cent,  of  paraffine  oil 
(neutral  oil  for  instance)  reduces  the  hydrometer  ^°. 

Iodine  Value.     Hann's  Method. 

"Weigh  in  a  small  glass  capsule  from  0.2  to  0.25  gram  of  oil. 
Transfer  to  a  350  cc.  bottle  having  a  well-ground  stopper.  Dis- 
solve the  oil  in  10  cc.  of  chloroform  and  add  30  cc.  of  Hann's 
solution  (see  below).  I^et  it  stand  with  occasional  shaking  for 
I  hour.  Add  20  cc.  of  a  10  per  cent,  solution  of  potassium  iodide 
and  150  cc.  of  water,  and  titrate  with  standard  sodium  thiosul- 

^  A  simple  colorimeter  for  general  purpose,  as  used  by  the  Department  of  Agricul- 
ture, United  States  Government,  and  designed  by  Mr.  Oswald  Schreiner,  is  described 
in  Journal  American  Chemical  Society,   September,    1905. 


454  ENGINEERING    CHEMISTRY 

phate,  using  starch  as  an  indicator.  Blanks  must  be  run  each 
time, 

"From  the  difference  of  the  amounts  of  sodium  thiosulphate 
required  by  the  blanks  and  the  determination,  calculate  the  iodine 
number  (centigrams  of  iodine  to  i  gram  of  oil). 

"The  iodine  number  of  raw  linseed  oil  varies  from  175  to  193, 
though  Gill  states  that  a  pure  raw  oil  may  run  as  low  as  160. 
Boiled  oil  may  be  very  much  lower. 

"Make  the  Hann's  solution  by  dissolving  13.2  grams  of  iodine 
in  1,000  cc.  of  glacial  acetic  acid,  which  will  not  reduce  chromic 
acid,  and  add  3  cc.  of  bromine."  (P.  H.  Wai^ker.) 

Specifications  for  Raw  Linseed  Oil.    Issued  by  the  Navy 
Department,  August  2,  1915. 

Superseding  Specifications  52-O-1,  issued  Aug.  15,  1912. 
Generai,  Instructions. 

1.  General  Specifications  for  Inspection  of  Material,  issued  by  the 
Navy  Department,  in  effect  at  date  of  opening  of  bids,  shall  form  part 
of  these  specifications. 

QUAUTY. 

2.  Raw  linseed  oil  shall  be  strictly  pure,  well-settled  oil,  perfectly 
clear  and  free  from  foots. 

Chemicai,  Constants. 

3.  The  oil  shall  show  upon  examination : 

Maximum  Minimum 

(Percent.)  (Percent.) 

Loss  on  heating  ^  hour  at  103°  to  105°  C 0.2  

Specific  gravity  at  15.5°   C 0.937  0.932 

Iodine  number   (Hann's)    .< 190.0  178.0 

Saponification  number    192.0  189.0 

Acid  number  30  

Refractive  index  at  25°   C 1.4805  1.479 

Unsaponifiable  matter    1.5  

Physical,  Characteristics. 

4.  The  oil  when  flowed  on  a  glass  plate,  which  is  held  in  a  position 
inclined  30°  to  the  vertical,  shall  dry  practically  free  from  tackiness  in 
75  hours  at  a  temperature  of  60°  to  80°  F. 

Basis  oe  Purchase. 

5.  To  be  purchased  by  the  commercial  gallon  and  inspected  by  weight. 
The  number  of  gallons  to  be  determined  at  the  rate  of  7^  pounds  of  oil 
to  the  gallon. 


ENGINEERING   CHEMISTRY  455 

Specifications  for  Boiled  Linseed  Oil.    Issued  by  the  Navy- 
Department,  February  2,  1914. 

Superseding  Specifications  S2-O-2,  issued  Nov.  20,  191 1. 

Composition. 

1.  Boiled  linseed  oil  shall  be  absolutely  pure  boiled  oil  of  high  grade, 
made  wholly  by  heating  pure  linseed  oil  to  over  350°  F.  with  oxides  of 
lead  and  manganese  for  a  sufficient  length  of  time  to  secure  a  proper 
combination  of  the  constituents  and  be  properly  clarified  by  settling  or 
other  suitable  treatment.  Evidence  of  the  presence  of  any  matter  not 
resulting  solely  from  the  combination  of  the  linseed  oil  with  the  oxides 
of  lead  and  manganese  will  be  considered  grounds  for  rejection. 

Chemicai,  Constants.  / 

2.  The  oil  shall  upon  examination  show : 

Unsaponifiable  matter Not  more  than  1.5  per  cent. 

Lead  oxide  (PbO) Not  less  than  0.20  per  cent. 

Manganese  oxide  (MnO) Not  less  than  0.04  per  cent. 

Iodine  number   (Hanus) Not  less  than  178. 

Specific  gravity  at  60°  F Not  less  than  0.938. 

The  oil  shall  give  no  appreciable  loss  at  212°  F.  in  a  current  of 
hydrogen. 

Physicai.  Characteristics. 

3.  When  flowed  on  glass  and  held  in  a  vertical  position,  the  oil  shall 
dry  practically  free  from  tackiness  in  12  hours  at  a  temperature  of 
70°  F. 

Basis  of  Purchase. 

4.  To  be  purchased  by  the  commercial  gallon;  to  be  inspected  by 
weight,  and  the  number  of  gallons  to  be  determined  at  the  rate  of  T^/z 
pounds  of  oil  to  the  gallon. 


FUEL  OIL. 


Characteristics  and  Testing  of  Fuel  Oil.^ 

From  the  standpoint  of  the  petroleum  trade,  fuel  oil  in  general 
includes  all  oils  w^hich  are  not  saleable  for  some  other  special 
purpose  at  a  higher  price  than  that  which  prevails  for  oils  to  be 
sold  as  fuel  oils,  to  be  burned  under  boilers.     From  the  trade 

^  Characteristics  and  Testing  of  Fuel  Oil,  prepared  by  Thomas  B.  Stillman,  Jr.,  of 
the  Babcock  and  Wilcox  Co.  Engineering  staff,  who  has  made  a  specialty  of  the  appli- 
cation of  fuel  oil  to  steam  generation. 


456  e;ngine:e:ring  che:mistry 

point  of  view,  it  also  includes  special  distillates  which  are  sold 
as  Diesel  oils.  It  does  not  include  various  distillates  burned  for 
power  purposes,  such  as  gasolene,  naphtha,  motor  spirits,  and 
various  kerosene  distillates.  The  actual  amount  of  oil  devoted  to 
fuel  purposes  varies  continually  with  the  condition  of  the  produc- 
tion of  crude  petroleums.  During  the  time  of  flush  production, 
such  as  has  existed  in  the  Oklahoma  fields  during  the  past  year 
due  to  the  extraordinary  production  in  the  Gushing  field,  a  great 
deal  of  crude  petroleum  is  sold  as  fuel  oil  on  account  of  the  neces- 
sity of  disposing  of  it  when  no  better  market  is  available.  The 
use  of  such  oil  is  not  advisable  for  fuel  purposes,  not  only  be- 
cause it  contains  valuable  gasolene  and  kerosene,  but  these  con- 
tents so  lower  the  flashing  point  of  the  fuel  oil  as  to  make  it  open 
to  the  objections  to  gasolene  stored  in  a  confined  space,  as  in  a 
battleship,  where  the  vapor  is  liable  to  produce  explosions  on  con- 
tact with  air. 

"Until  the  last  twelve  months,  much  of  the  production  of  Cali- 
fornia crude  oil  was  sold  for  fuel  purposes  practically  as  it  came 
from  the  well.  Within  the  last  year,  however,  the  practice  of 
topping  off  the  valuable  gasolene  and  kerosene  in  a  compara- 
tively small  proportion  of  California  oils  has  so  increased  that 
not  more  than  25  per  cent,  of  the  fuel  oil  of  California  is  now 
crude  oil.  In  States  other  than  California  and  Oklahoma,  and 
to  a  slight  extent  Texas,  fuel  oils  consist  chiefly  of  the  least  valu- 
able distillates  and  some  residuum.  The  distillates  of  such  low 
value  as  to  be  sold  for  fuel  are  usually  the  products  distilling 
off  after  kerosene,  and  those  too  heavy  for  burning  in  lamps  and 
also  too  thin  to  be  used  as  lubricating  oils.  Such  oils  generally 
have  the  name  of  gas  oils,  and  are  more  valuable  for  use  as  gas 
oils  than  for  fuel  purposes,  but  the  market  for  gas  oils  is  easily 
over-supplied,  and  the  surplus  goes  for  fuel  oil. 

The  annual  production  of  petroleum  in  the  United  States  is 
about  266,000,000  barrels,^  of  which  at  least  100,000,000  barrels 
is  consumed  as  fuel.  This  proportion  will  hold  fairly  well  for  the 
petroleum  production  of  the  world,  that  is,  about  ^  of  the  world's 

1  Dr.  David  T.  Day. — Director  of  U.  S.  Bureau  of  Mines,   1915. 


ENGINEERING   CHEMISTRY  457 

production  may  be  considered  "fuel  oil."  In  regions  such  as  the 
East  Indies,  the  petroleum  is  to  a  large  extent  too  valuable  for 
use  as  fuel.  This  is  offset  by  Mexico  and  Russia,  where  the  use 
of  residuum  and  even  crude  oil  for  fuel  purposes  is  very  gen- 
eral, and  exceeds  the  average  proportion. 

There  are  three  kinds  of  petroleum  in  use,  namely,  those  yield- 
ing on  distillation — 

1st.     Paraffin; 
2nd.     Asphalt  ; 
3rd.     Olefine. 

To  the  first  group  belong  the  oils  of  the  Appalachian  range, 
and  the  middle-west  of  the  United  States.  These  are  dark  brown 
in  color  with  a  greenish  tinge.  Upon  their  distillation  such  a 
variety  of  valuable  light  oils  are  obtained  that  their  use  in  the 
crude  condition  as  fuel  is  prohibitive  because  of  price. 

To  the  second  group  belong  the  oils  found  in  Texas  and  Cali- 
fornia and  in  Mexico.  These  vary  in  color  from  a  reddish 
brown  to  a  jet  black  and  are  used  very  largely  for  fuel. 

The  third  group  comprises  the  oils  from  Russia,  which,  like 
the  second,  are  largely  for  fuel  purposes. 

^Whether  or  not  it  "pays"  to  use  oil  depends  on  many  things. 
There  may  be  reasons  that  makes  its  adoption  imperative  at  prac- 
tically any  cost — certain  military  advantages  for  instances — such 
as  smoke  prevention,  speed  of  vessel,  etc.,  but  the  merchant 
owner  will  be  influenced 

1st.  By  comparative  cost  of  coal,  wood  or  fuel  delivered  at  the 
boiler ; 

2nd.  Relative  heat  value  of  the  fuel; 

3rd.  Relative  capacity  and  efficiency  in  steam  production. 

This  may  result  in  being  able  to  run  a  plant  natural  draft  with 
oil  instead  of  forced  draft  with  coal,  thus  saving  the  cost  of  in- 

^  E.  H.  Peabody,  Member  Am.  Soc.  M.  E.,  Soc.  N.  A.  M.  E.,  in  paper  read  before 
the  International   Engineering  Congress,   San  Francisco,   California,    1915. 


458  e:ngine:e:ring  che:mistry 

stalling  and  operating  blowers,  or  in  the  installation  of  less  boiler 
power. 

4th.  Expense  of  fitting  up  for  oil  including  suitable  storage 
provisions  for  the  fuel. 

•  5th.  Saving  in  labor  due  to  reduction  in  number  of  firemen, 
elimination  of  coal  passers,  and  the  expense  of  removal  of  ashes. 

6th.  Increased  life  of  boilers  and  lower  maintenance  charges, 
both  in  the  fireroom  and  the  engine  room. 

When  considering  marine  installations,  the  following  two 
points  : 

7th.  Increased  bunker  capacity  and  longer  steaming  radius. 

8th.  Time  saved  on  voyage  due  to  steadier  steam  pressure  and 
possible  time  saved  in  fueling  ship. 

In  round  numbers,  as  a  steam  producer,  a  pound  of  oil  is  equal 
to  a  pound  and  a  half  of  coal,  or  approximately  one  ton  of  coal  is 
equal  to  four  and  one  half  barrels  of  oil,  or  to  quote  another  ap- 
proximate but  handy  rule,  one  ton  of  coal  equals  two  hundred 
gallons  of  oil.  Mr.  Walter  M.  McFarland  has  derived  a  simple 
relationship  between  the  relative  costs  of  oil  and  coal  as  follows : 

2A  =  B. 

Where  A  1=  cost  of  oil  in  cents  per  gallon  (7.88  pounds),  and 
the  B  ^  the  cost  of  coal  in  dollars  per  ton  (2,240  pounds).  Thus, 
when  the  cost  of  coal  in  dollars  per  ton  is  double  the  cost  of  oil 
in  cents  per  gallon  the  fuel  costs  of  producing  steam  will  be  ap- 
proximately equal. 

While  no  general  statement  of  cost  can  be  used  for  obtaining 
more  than  an  approximation  for  individual  cases,  it  is  hoped  that 
what  is  given  above  may  be  of  some  assistance  in  showing  the 
many  advantages  of  oil  over  coal  fuel  and  the  probability  of  its 
saving  money. 

To  indicate  the  requirements  of  a  good  fuel  oil  the  following 
specifications  used  in  the  purchase  of  fuel  oil  for  the  U.  S.  Navy 
may  prove  of  interest : 


ENGINEERING   CHEMISTRY  459 

(a)  Fuel  oil  shall  be  a  hydrocarbon  oil  of  best  quality,  free 
from  grit,  acid,  or  fibrous  and  other  foreign  matter  likely  to  clog 
or  injure  the  burners  or  valves. 

(b)  The  unit  of  quantity  to  be  the  barrel  of  42  gallons  of  231 
cubic  inches  at  a  standard  temperature  of  60°  F.  For  every  vari- 
ation of  temperature  of  10°  F.  from  the  standard  0.4  of  i  per 
cent,  shall  be  added  or  deducted  from  the  measured  or  gauged 
quantity  for  correction. 

(c)  Flash  point  never  under  150°  F.  as  a  minimum  (Abel  or 
Pensky-Marten's  closed  cup),  or  175°  F.  (Tagliabue  open  cup), 
and  not  lower  than  the  temperature  at  which  the  oil  has  a  viscos- 
ity of  8°  Engler  (water  =  i  Engler).  (Example:  If  an  oil  has 
a  viscosity  of  8°  Engler  when  heated  to  186°  F.  then  186°  is  the 
minimum  flash  point  at  which  this  oil  will  be  accepted.) 

(d)  Viscosity  at  100°  F.  not  greater  than  200°  Engler. 

(e)  Water  and  sediment  not  over  i  per  cent.  If  in  excess  of 
I  per  cent,  the  excess  to  be  subtracted  from  the  volume;  or  the 
oil  may  be  rejected. 

Note. — If  an  Engler  viscosimeter  is  not  available,  the  Saybolt 
standard  universal  viscosimeter  may  be  used,  and  280  seconds 
Saybolt  will  be  considered  equivalent  to  8°  Engler,  and  7,000 
seconds  Saybolt  will  be  considered  equivalent  to  200°  Engler. 
Water  at  60°  F.  =  30  seconds  Saybolt.  Water  and  sediment  will 
be  taken  by  the  distillation  method.  When  oil  in  small  lots  is 
consigned  to  naval  vessels  or  to  navy  yards,  the  centrifuge  test 
will  be  used  in  order  to  obviate  delay.  In  this  test  50  cc.  of  oil 
and  an  equal  quantity  of  the  best  commercial  benzol,  50  per  cent, 
white,  will  be  used,  and  the  mixture  heated  to  100°  F. 

The  "flash  point"  of  fuel  oil  is  the  temperature  at  which  it 
gives  off  inflammable  gases,  and  is  a  question  of  irhportance  in 
determining  its  availability  as  a  fuel.  In  general  it  may  be  stated 
that  the  light  oils  have  a  low  and  the  heavy  oils  a  much  higher 
flash  point.  There  are,  however,  many  exceptions  to  this  rule ;  as 
for  example;  some  of  the. heaviest  Mexican  crude  oils  of  11°  to 
12°  Baume  frequently  have  flash  points  of  100°  or  125°  F.     As 


460  ENGINEERING   CHEMISTRY 

the  flash  point  is  lower  the  danger  of  ignition  or  explosion  be- 
comes greater,  and  the  utmost  care  should  be  taken  in  handling 
the  oils  with  a  low  flash  point  to  avoid  this  danger.  On  the  other 
hand,  because  the  flash  point  is  high,  is  no  justification  for  care- 
lessness in  handling  these  fuels.  With  proper  precautions  taken, 
in  general,  the  use  of  oil  as  fuel  is  practically  as  safe  as  the  use 
of  coal. 

The  Baume  hydrometer  scale  for  liquids  lighter  than  water 
has  obtained  a  stronghold  in  the  fuel  oil  industry,  and  for  light 
oils  this  practice  is  justified  by  the  ease  with  which  the  gravity 
may  be  determined;  namely,  by  the  simple  reading  of  the  scale 
on  the  stem  of  the  hydrometer  immersed  in  the  liquid.  But  for 
heavy  viscous  oils,  the  very  nature  of  the  oil  makes  this  process 
a  slow  one  and  liable  to  considerable  error.  It  is  believed  by 
some,  that  for  these  oils  it  is  much  better  to  determine  the  weight 
of  a  known  volume  of  the  oil  (as  in  the  specific  gravity  bottle), 
and  report  the  density  in  terms  of  the  density  of  water  at  60°  F., 
i.  e.,  as  specific  gravity. 

On  the  other  hand,  there  are  advocates  of  the  method  of  heat- 
ing viscous  oils  sufficiently  to  make  the  use  of  the  Baume  hydrom- 
eter feasible,  making  the  necessary  corrections  in  temperature. 
The  specific  gravity  bottle  method  is,  however,  to  be  preferred 
for  accurate  work,  as  it  eliminates  the  possible  error  which  may 
be  introduced  by  the  temperature  correction,  which  varies  for 
different  oils. 

The  United  States  Bureau  of  Standards  has  adopted  the  fol- 
lowing formula  for  converting  readings  on  the  Baume  scale 
lighter  than  water,  to  terms  of  specific  gravity. 

Specific  gravity   at  60°  F.  = ■ — ~ 

^  &         ^  130  -f  Baume 

The  conversion  table  on  the  following  page  is  given  for  handy 
reference : 


e:nginee:ring  chemistry 


461 


Baum6 


10 
II 
12 
13 

14 
15 
16 

17 
18 

19 

20 

21 
22 
23 
24 
25 
26 

27 

28 

29 
30 

35 

40 


Specific 
gravity  at 

60°  F. 


1. 000 

0-993 
0.986 
0.980 

0.973 
0.966 

0-959 
0.952 
0.946 
0.940 

0.933 
0.927 
0.921 

0.915 
0.909 
0.903 
0.897 
0.892 
0.886 
0.8S1 

0.875 
0.848 


Weight  in  pounds — 60°  F. 


Per  U.  S. 
gal. 


8.337 
8.280 
8.222 

8. 171 
8.112 
8.054 
7.996 
7-937 
7.887 
7.837 
7-779 
7.729 
7.679 
7.629 
7.579 
7-529 
7-479 
7-437 
7-387 
7-345 
7-295 
7.070 
6.862 


Per 
cu.  ft. 


62.368 
61.931 

61.495 
61. 121 
60.684 
60.247 
59.811 

59-374 
59.000 
58.626 
58.189 
57.815 
57-441 
57-067 
56.693 
56.318 
55-944 
55-632 
55.258 
54.946 
54-572 
52.888 

51-329 


Per  barrel 
(42  gal.) 


350.17 
347-72 
345-32 
343-17 
340.70 
338.27 
335-82 
333-35 
331.25 
329.15 
326.71 
324.61 
322.51 
320.42 

318.31 
3x6.21 
314.10 

312.35 
310.25 
308.50 
306.40 
296.94 
288.20 


The  specific  heat  of  fuel  oil  varies  with  its  composition.  It 
will  be  greater  the  richer  the  oil  is  in  hydrogen,  and  lower  in  pro- 
portion to  a  greater  carbon  content.  The  following  figures  are 
reproduced  from  Holde's  work  on  examination  of  hydrocarbon 
oil:^ 


Crude  oil  from 


Japan  

Pennsylvania 

Russia 

California  • . . 


Specific  heat 


0.435 
0.500 

0.435 
0.398 


With  the  advent  of  the  viscous  crude  oils  of  Mexico,  and  the 
increased  use  of  the  heavy  distillates  from  other  fields,  coupled 
with  the  wider  adoption  of  mechanical  atomizers,  the  degree  of 
the  viscosity  of  the  oil  becomes  a  matter  of  considerable  import- 


1  Published  by  John  Wiley  &  Sons,  1915. 


462  ENGINEERING   CHEMISTRY 

ance.  A  description  of  different  viscosimeters  and  the  methods 
of  using  them  are  explained  at  length  in  other  parts  of  this  book. 
The  following  points  in  regard  to  the  value  of  viscosity  as  ap- 
plied to  fuel  oils  are  of  importance. 

In  handling  oil  through  the  pumps  and  piping  of  a  fuel  oil 
system  it  is  necessary  to  have  its  viscosity  reduced  to  at  least 
375°  Engler,  and  preferably  to  300°.  These  figures  also  hold 
for  the  delivery  of  fuel  oil  to  steam  or  air  atomizing  burners, 
where  the  steam  or  air  is  the  medium  used  for  atomizing  the  oil 
and  delivering  it  in  a  fine  spray  in  the  furnace.  In  the  case  of  a 
mechanical  atomizing  burner,  however,  it  is  necessary  to  reduce 
the  viscosity  to  8°  Engler  before  the  oil  will  give  a  satisfactory 
atomization,  this  figure  of  8°  applying  particularly  to  the  better 
grades  of  oils,  such  as  navy  standard.  In  the  case  of  the  heavy 
Mexican  oils  a  viscosity  of  10°  to  12°  Engler  is  sufficiently  low  to 
produce  an  atomization  which  is  the  equal  of  that  given  by  the 
better  grades  of  oil  at  8°  Engler.  In  all  cases  where  mechanical 
atomizers  are  used  it  is  better  to  reduce  the  viscosity  below  8°  (or 
12°  as  the  case  may  be)  as  in  general,  the  lower  the  viscosity,  the 
less  tendency  there  is  for  the  burners  to  produce  smoke. 

Certain  grades  of  the  heavier  oils  contain  considerable  sul- 
phur, and  the  question  is  frequently  asked  whether  or  not  cor- 
rosion from  this  cause  may  result.  Experience  has  demonstrated 
that  sulphur  in  oil  has  no  bad  effect  on  boilers,  except  in  cases  of 
neglect,  when  pitting  may  occur  under  certain  conditions,  as  with 
coal. 

Corrosion  of  copper  heating  coils  has,  however,  been  noticed 
in  the  presence  of  sulphur-bearing  oils,  and  for  this  reason,  it  is 
the  recognized  practice  to  use  steel  coils.  Brass  and  bronze  fit- 
tings may  be  used  however,  with  safety,  both  on  pumps  and  on 
pipe  lines. 

The  function  of  an  oil  burner  is  to  atomize  or  vaporize  the 
fuel  so  that  it  may  be  burned  like  a  gas.  All  burners  may  be 
classified  under  two  general  types : 

1st.  Spray  burners,  in  which  the  oil  is  atomized  by  steam  or 
compressed  air; 


ENGINEE^RING   CHEMISTRY  463 

2nd.  Mechanical  burners,  in  which  the  oil  is  atomized  by  sub- 
mitting it  to  a  high  pressure  and  passing  it  through  a  small 
orifice. 

Spray  burners  are  almost  universally  used  for  land  practice 
and  the  simplicity  of  the  steam  atomizer  and  the  excellent  econ- 
omy of  the  better  types  together  with  the  low  oil  pressure  and 
temperature  required  makes  this  type  a  favorite  for  stationary 
plants,  where  loss  of  fresh  water  is  not  a  vital  consideration.  In 
marine  work  or  in  any  case  where  it  is  advisable  to  save  feed 
water  that  otherwise  would  have  to  be  added  in  the  form  of 
"make-up,"  either  compressed  air  or  mechanical  means  are  used 
for  atomization.  Spray  burners  using  compressed  air  as  the 
atomizing  agent, are  in  satisfactory  operation  in  some  plants,  but 
their  use  is  not  general.  The  air  burners  require  blowers,  com- 
pressors, or  other  apparatus  which  occupy  space  that  might  be 
otherwise  utilized,  and  require  attention  that  is  not  necessary 
when  steam  is  used. 

Where  burners  of  the  steam  or  air  type  are  used,  heating  the 
oil  is  an  advantage,  not  only  in  causing  it  to  atomize  more  easily, 
but  in  aiding  economical  combustion.  In  the  case  of  mechanical 
atomizers  it  is  necessary  to  warm  the  oil  until  its  viscosity  is 
reduced  to  at  least  8°  Engler,  as  noted  above.  The  temperature 
is,  of  course  limited  somewhat  by  the  flash  point  of  the  oil  used 
especially  in  navy  work,  but  as  heavy  Mexican  oils  with  a  flash 
point  of  125°  F.  have  been  frequently  raised  to  280°  F.  to  burn 
them  satisfactorily  in  mechanical  burners,  without  serious  results, 
there  seems  to  be  no  reason  why  the  temperature  should  not  be 
carried  above  the  flash  point,  if  necessary,  provided  it  is  not 
carried  high  enough  to  cause  decomposition  of  the  oil  or  a  carbon 
deposit  in  the  supply  pipe.  In  the  case  of  steam  atomizers  if 
the  temperature  is  raised  to  a  point  where  an  appreciable  vapori- 
zation occurs,  the  oil  will  flow  irregularly  from  the  burner,  and 
cause  the  flame  to  sputter. 

The  mechanical  system  of  burning  oil  is  especially  adapted 
for  marine  work  as  the  quantity  of  steam  required  for  putting 
pressure  on  the  oil  is  small,  and  the  condensed  steam  may  be 


464  ENGINEERING   CHEMISTRY 

returned  to  the  system.  The  only  method  by  which  successful 
mechanical  atomization  has  been  accomplished  is  the  one  in  which 
the  oil  is  given  a  whirling  motion  within  the  burner  tip.  This  is 
done  either  by  forcing  the  oil  through  a  passage  of  helical  form 
or  by  delivering  it  tangentially  to  a  circular  chamber  from  w^hich 
there  is  a  central  outlet.  The  oil  is  fed  to  these  burners  under 
a  pressure  that  varies  with  the  make  of  the  burner  and  the  rate 
at  which  each  individual  burner  is  using  oil,  and  is  usually  be- 
tween 50  and  200  pounds  to  the  square  inch.  The  oil  particles 
fly  off  from  such  a  burner  in  straight  lines  in  the  form  of  a  cone 
rather  than  in  the  form  of  a  spiral  spray,  as  might  be  supposed. 

Where,  in  the  spray  burners,  air  for  combustion,  is  ordinarily 
admitted  through  a  checker-work  under  the  burner  proper,  in  the 
mechanical  burner,  it  is  almost  universally  admitted  around  the 
burner  and  the  problem  of  properly  mixing  the  air  with  the  spray 
of  oil  under  these  conditions  is  such  a  difficult  one  that  very  few 
burner  manufacturers  have  satisfactorily  solved  it,  they  usually 
being  well  contented  to  obtain  10  to  11  per  cent.  COg  in  the  flue 
gases,  without  CO.  It  is,  however,  possible  to  obtain  as  high  as 
14^  per  cent.  CO^  without  CO  by  giving  the  air  a  proper  "twist" 
as  it  enters  around  the  burner,  and  it  was  with  burners  using  this 
principle  that  the  excellent  results  shown  below  were  obtained. 

To  give  an  idea  of  the  importance  of  the  composition  of  the 
flue  gases  in  burning  oil  under  boilers  the  following  table  is 
given  showing  the  rapid  loss  in  boiler  efficiency,  as  the  percentage 
of  CO2  in  the  flue  gas  goes  down.  The  presence  of  CO  in  the 
flue  gas  is  another  cause  for  lost  efficiency  which  must  be  guarded 
against.  Also  the  oil  must  be  burned  with  practically  no  smoke, 
as  a  heavy  oil  smoke  produces  a  tarry  carbon  deposit  on  the 
boiler  tubes  which  it  is  difficult  to  remove  and  which  prevents 
the  proper  transfer  of  heat  to  the  water  in  the  boiler. 


ENGINEERING   CHEMISTRY 


465 


Boiler  Efficiencies— Oil  Fuel.* 

Showing  the  maximum  theoretical  efficiency,   for  a  given  per  cent,  excess 

air  supply  and  flue  gas  temperature,  based  on  assumptions  stated  below. 


As- 
sum- 

Assumed temperature  of  flue  gases— Fahr. 

As- 
sum- 

ed 

ed 

Per 

1 

Per 

cent. 

375° 

400° 

425° 

450° 

475^ 

500°        550° 

600° 

700° 

800° 

cent. 

ex- 

ex- 

cess 

cess 

sup'y 

Calculated  boiler  efficiency,  Per  cent. 

air 
sup'y 

0 

81.35 

80.78 

80.20 

79.61 

79.03 

78.44 

77.28 

76.11 

73-77 

71.43 

0 

10 

80.62 

So.  04 

7941 

78.78 

78.15 

77.52 

76.25 

74.99 

72.47 

69.94 

10 

50 

77.90 

77.08 

76.25 

75.44 

74.62 

73.80 

72.16 

70.52 

67.24 

63-97 

50 

ICO 

74.42 

73-37 

72.32 

71.26 

70.21 

69.16 

67.04 

64-95 

60.72 

56.51 

100 

150 

65.79 

64.51 

61.93 

59-35 

54.20 

49.04 

150 

200 

59.86 

56.81 

53.77 

47.67 

41.58 

200 

250 

51.69 

48.18 

41.15 

34-11 

250 

300 

46.58 

42.60 

34.63 

26.65 

300 

Approximate  relation  between  per  cent,  CO2  and  excess  air  supply 
as  per  assumptions  below. 


Per  cent.  Co., 

' 

5 

6 

7 

8 

9 

10 

II 

12 

13 

14 

15 

15-9 

Per   cent,    excess 

gjj- 

283 

-5 

155 

120 

93.0 

72.2 

55.5 

41.9 

30.6 

21.0 

12.7 

5.6 

0 

1  This  table  was  prepared  by  Chas.  C.  Moore  &  Co.,  Engineers,  San  Francisco,  Cal. 

Values  in  above- table  are  conditioned  on  the  following  assump- 
tions : 

Average  temperature  of  air  for  combustion  entering  the  boiler, 
80°  F. ;  humidity,  80  per  cent. ;  air  per  pound  of  oil  chemically 
required  for  complete  combustion,  14  pounds ;  B.  t.  u.  per 
pound  of  oil  as  fired,  18,500;  chemical  composition  of  the  oil  as 
follows:  carbon,  86  per  cent.;  hydrogen,  11  per  cent.;  sulphur, 
0.8  per  cent. ;  nitrogen,  0.2  per  cent. ;  oxygen,  i.o  per  cent. ;  water, 
i.o  per  cent. 

Per  cent,  of  excess  air  stated  is  measured  at  boiler  outlet  and 
consequently  includes  leakage  through  boiler  setting. 

The  loss  by  radiation  has  been  taken  as  3  per  cent.  This  loss 
varies  with  the  size  of  boiler,  insulation,  etc.,  being  less  than 
30 


466 


ENGINEERING   CHEMISTRY 


indicated  for  larger  sizes  of  boilers  and  greater  for  smaller  sizes. 
An  allowance  of  2  per  cent,  for  undetermined  losses  has  been 
made.  This  quantity  is  subject  to  considerable  variation  and 
may,  in  exceptionally  favorable  instances,  be  as  low  as  0.5  per 
cent. 

The  following  constants  are  taken  from  Marks  and  Davis' 
steam  tables :  Absolute  temperature, — 459.6°  F.  Heat  of  vapor- 
ization at  atmospheric  pressure,  970.4  B.  t.  u.  Specific  heat  of 
superheated  steam  at  atmospheric  pressure,  for  the  range  of  tem- 
perature from  212°  to  700°  F.,  47. 

To  give  an  idea  of  the  results  which  may  be  obtained  under 
the  best  conditions  with  steam  atomizers,  the  following  boiler 
tests  made  on  a  600  horse-power  Babcock  &  Wilcox  stationary 
type  of  boiler,  using  Peabody  steam  atomizers  in  conjunction 
with  a  Peabody  furnace,  by  Doctor  D.  S.  Jacobus^,  are  given: 


Date— 1907-08 


Duration  of  test,  hours 

Steam  pressure,  by  gauge 

Temperature  of  feed  water 

Factor  of  evaporation 

Draft  in  furnace— inches  of  water  . 

Draft  at  damper 

Temperature  of  flue  gases  °F.    .... 

Flue  gas  analysis,  %  bv  volume  •  • 

CO2 •' 

O 

CO 

N 

Oil  burned  per  hour 

Water  evaporated  per  hour,  from 
and  at  2 1 2° 

Evaporation  from  and  at  212°  per 
pound  of  oil 

Per  cent,  of  rated  capacity  devel- 
oped   

B,  t.  u.  per  pound  of  oil 

EflEiciency  of  boiler 


Dec.  28 

Dec.  30 

Dec.  31 

8 

8 

8 

183.1 

182.4 

178.9 

141. 8 

144.2 

160.7 

I-I793 

1. 1956 

1.1526 

0.03 

0.2[ 

0.03 

0.03 

0.38 

0.02 

401.4 

492.9 

378.4 

1350 

1268 

13.90 

2.91 

3-43 

2,12 

0.06 

0.29 

0.22 

83.53 

83.60 

83.76 

1,436.0 

2,705.0 

938.0 

22,052.0 

38,340.0 

14,234.0 

15.37 

14.17 

15.18 

105.8 

183.9 

68.3 

17.S46 

17,839 

17,682 

83.58 

77.08 

83.31 

Jan.  13 


8 

183. 1 

147.3 
1. 1665 

0.035 
0.006 

364.1 


578.0 
8,869.0 

15.35 

42.6 

17.871 

83.35 


The  heat  balances^  for  the  above  tests  are  as  follows  : 

1  Formerly  Professor  of  Experimental  Engineering,  Stevens  Institute,  and  at  present 
Advisory  Engineer  of  the  Babcock  and  Wilcox  Co. 

-  For  method  of  calculating  Heat  Balances.     See  "  Boiler  Testing." 


ENGINEERING   CHEMISTRY 


467 


Date 


Heat  absorbed  by  boiler 

Loss  due  to  moisture  in  oil 

' «      "    "  moisture  from  burning 

H. 

Loss  due  to  heat  in  dry  gases 

"       "    "  CO 

((       a    "  radiation,  etc. 

Total 


Dec.  28 


B.  t.  u.        Per  cent. 


14915.O 
20.4 

1225.4 

1274.4 

19.5 

391.3 


17846.0 


83.58 
O.  II 

6.86 

7.14 
o.ii 
2.20 


100.00 


Dec.  30. 


B.  t.  u.         Per  cent. 


13750.6 
9.9 

1277.7 

2309.7 

185.0 

306.1 


17839.0 


77.08 
0.06 

7.16 

12.95 

1.04 

I.71 


100,00 


Date 


Heat  absorbed  by  boiler 

Loss  due  to  moisture  in  oil 

"       "    "  moisture  from  burning 

H.    

Loss  due  to  heat  in  dry  gases 

"       "    '*  CO 

"       •'    "  Radiation,  etc. 

Total 


Dec.  31 


B.  t.  u.        Per  cent. 


14730.7 
14.9 

1221.4 

1296.4 

54.3 

364.3 


17682.0 


83.31 
0.08 

6.91 

7.33 
0.31 
2.06 


Jan. 13 


B.  t.  u.        Per  cent. 


14895.6 
16.6 

I214.9 

1238.0 

33.6 

472.3 


17871.O 


83.35 
0.09 

6.80 

6.93 
0.19 
2.64 


Under  careful  operating  conditions,  using  the  best  type  of 
steam  atomizers  approximately  2  per  cent,  of  the  steam  gener- 
ated by  the  boiler  will  be  used  in  atomizing  the  oil.  If  the  tem- 
perature of  the  oil  is  reduced  until  its  viscosity  is  low  (10°  or  15° 
Engler),  less  steam  is  required  to  produce  perfect  atomization, 
the  steam  consumption  in  actual  practice,  under  these  conditions, 
having  been  reduced  to  one  half  of  one  per  cent,  of  the  steam 
generated  by  the  boiler. 

As  an  illustration  of  what  may  be  expected  when  burning  oil 
with  mechanical  atomizers,  the  following  tests  are  given  as  repre- 
sentative of  good  practice: 


468 


ENGINEERING   CHEMISTRY 


<  3 


go 


o  ^ 


CCS 


•o'n 


rj-^  >,cOO 


ro  CjN'^-'.  CO      -      •      •      •     ' 


CO   _    o 


^p  ^^8%!1^-S'-^  5?^^^^^o 


O   O 

I 


6   COCO   S   ^  ^.   ^-^  up  4^ 


^ 


lOvO 


On  <^.   -.    g  CO 

o  o  °  £; 


I    I 


^^a^ 


CO 


lO 


rO 


'o5 


v£)  _.  lO  lO  lO  ^ 

j^    •     ^  -.  ^  o  fo  ^  "?^  lo  ^  q^  O  CO  ^X 


^^  ^  lOOO  CO  '^^ 


O   u 


'OOrOf^(N(NOt  f^.CO   f^CO  "^^     •      •      •  . 


«     ON 


t-c  I      I    -p  '-'  O    (s    '^        CO 


r>»  ^       ^   (M     —     /-^ 


:?^8-8'8g,Sa^S>^=o. 


o  o 


<N      I 


en     . 


c  G  c  a  c 

uaa;a> <d 

^  ^  Xi  X>  Xi  Xi  Xi 
1>    3J    CJ    ^'^'^'^•"^•^'~''~<    ^ 

c-  :u  a-  Cu  cu 


ENGINEERING   CHEMISTRY 


469 


^. 

1 

5 

0    >-    rO        VO 

8 

8 

4; 

ci  r^^    1    T^ 

VO 

CO    t-^  On    '     Tt- 

8 

fn 

HH 

U 

A 

<1 

K 

to  M    0           ON 
CN  CO    10    1     Tf 

q^  Ttco    1  00 
10  i-T  h-T 

a; 

^• 

_j 

;; 

CO    CM^  Ost^ 

8 

5 

0    10^    rOvO 

8 

0 

«N     ^     0  ^    t^ 

?i 

10  0   10  0  CO 

rO 

1 

toco  fo  d  pj 
t^      1-1 

8 

r^ 

1^ 

^d  r^  d  d  10 

8 

•r" 

K^ 

a 

c: 

< 

„• 

0    Tt  0     <N     0 

vO 

^ 

0  VO    0  VO  CO 

0 

vO    r^  «S    rO  CM 

0 

TT  r^  i—        vO 

CO    M    On         0 

4->' 

T*-     10    10    -^       10 

M 

^j 

0 

«■ 

T?  h-T   CN 

cR 

K 

CO  «    .."         hT 

od" 

^. 

J- 

to  0  0       to 

8 

j; 

lOCO   0^  cOTJ• 

8 

s 

0   -^  -^  c<  r-> 

t~^ 

0 

0; 

dr^c^l    ^ 

8 

0 

CN  vd  MD   I-;   Tt 
CO 

8 

^ 

fl, 

^ 

&, 

_• 

0  CO    tN          VO 

vO 

^ 

„• 

0    Tt  CO  1-    (N 

8 

'^ 

^  z^  "^   1    r^ 

0 

"^ 

to  t^  r^  .<^vO 

■M 

to  TfCO_    1     CO 

^ 

4J 

CO^  >->^  <^^       CO 

«■ 

10  i-T  hT 

2^ 

m 

Tt  >-^  hT 

co' 

S 

0    VOOO    .^  rO 

8 

s 

0  VO  ^  r^  CO 

8 

fj 

rj    ro  «    CN    q 

i; 

00    -^  CO  «    t-^ 

*o 

0 

;- 
0 

6  t^vd  d  ^' 

8 

0 
I- 
4; 

J  \o  vd  d  CO 

00 

8 

P, 

2 

p!, 

"o 

>> 

1 

0    to  M  VO    - 

'* 

0  0  t^  0  fO 

8 

"_ 

CN    0  CO    -^  to 

0 

-^ 

(N  r^  x^  CO  CO 

^ 

rO  rt;  -          m_ 

^ 

r^  «  '-<^       q_ 

P5 

to  "-•    ►-<          t-i 

a^ 

P5 

^  i-T  hT       m" 

00 

'"' 

'"' 

"^ 

.       .       -       .     k> 

.    .    .    .   t< 

•     0 

.   0 

.  Ci 

•  'd 

•  'd 

•     (U 

, 

*  ii 

*  s 

•   C 

•    3 

s 

:  0 

0 

.  0 

.    y 

a 

.  0 

a 

u 

o;  en    .   rt 

<U   cfi    .    rt 

tuoS    .   a 

bjO<u    .   c 

2^  :  =^ 

■n 

2  ^  :  ^ 

-O 

^'O  to  .n3 

1 

5n 
1 

.-^^^l   ^ 

- 

0  bfl'd   .  a 

^ 

2 

3^1  :§ 

f 

3 

ed  by 
burni 
heat  i 
CO... 
radiat 

t 

5 

»ed  by 
burni 
heati 
CO... 
radiat 

■£2::. 

1 

15^  =  = 

s 

CO    d) 

0 

_o   *"  -    -    - 

"p 

^  s:  :  - 

H 

H 

rtTS 

oJns" 

<u  n  -    -    - 

1^   en  ,    -    , 

;i 

.(  H 

? 

^ 

H  1- 

^. 

1 

470  ENGINEERING   CHEMISTRY 

In  these  tests  with  mechanical  atomizers  the  boiler  was  sur- 
rounded by  an  air-tight  room  into  which  air  could  be  forced 
under  pressure,  if  desired,  to  imitate  forced  draft  conditions  on 
ship  board,  and  in  this  way  the  high  rates  of  driving  were  ob- 
tained. 

In  general,  crude  oil  consists  of  carbon  and  hydrogen,  although 
it  also  contains  varying  quantities  of  moisture,  sulphur,  nitrogen, 
oxygen,  arsenic  phosphorus  and  silt,  the  moisture  contained  may 
vary  from  less  than  i  to  over  30  per  cent.,  depending  upon  the 
care  taken  to  separate  the  water  from  the  oil  in  pumping  from 
the  well.  As  in  any  fuel,  this  moisture  affects  the  available  heat 
of  the  oil,  and  in  contracting  for  the  purchase  of  fuel  of  this  na- 
ture it  is  well  to  limit  the  per  cent,  of  moisture  it  may  contain.  A 
large  portion  of  any  contained  moisture  can  be  separated  by  set- 
tling, and  for  this  reason  sufficient  storage  capacity  should  be 
supplied  to  provide  time  for  such  action. 

A  pound  of  petroleum  usually  has  a  calorific  value  of  18,000 
to  22,000  B.  t.  u.  an  ultimate  analysis  of  an  average  sample  be- 
ing— 

Per  cent. 

Carbon    84.0 

Hydrogen 14.0 

Oxygen    2.0 

and  assuming  that  the  oxygen  was  combined  with  the  equivalent 

of  hydrogen  to  form  water,  the  analysis  would  become — 

Per  cent. 

Carbon    84.00 

Hydrogen    13.75 

Water 2.25 

and  the  heat  value  per  pound  including  its  contained  water  w^ould 

be— 

B.  t.  u. 

Carbon    0.8400  X  14,600  =  12,264 

Hydrogen    0.1375  X  62,100  =    8,625 

Total   20,889 

The  nitrogen  in  petroleum  varies  from  0.008  to  i  per  cent., 

while  the  sulphur  varies  from  0.07  to  3  per  cent. 

The  following  Table^  compiled  from  various  sources  gives  the 

composition,  calorific  value,  and  other  data  relative  to  oils  from 

different  localities : 

^  From  35th  Edition  of  "Steam." 


ENGINieERING  CHEMISTRY 


471 


u  u  u 

.000 

X    s    S    3 
O  <+-■*»-'  «*< 

1— 1  'O  "^  "^ 

>  '5  '5  '3 
►^  cr  cr  cr" 


o 


o 
o 

I 

M 
u 

03   O    O 

CQ  K  P3 


I-   1/5  .2 

bcfl  o 
0(C  0, 


o<nooonooooi-'noo  <r>vo  o 

10  rO  1000    «-   Tl-  rj-  On  10  rO^    «-•  ,     "^ 

^           -           .  rOvO^  10  (N    f^^W  ^   "^  "^^  "^  "^  ^_ 

r^co"  cf^ScT'Od^d^d^d^  "-"co"  o"  on  o"  '-"00"  d\ 

M    —    p-i    —    hHCSi-ii-Hi-iH-iC^H-iM    —    CNCS—  I- 


t^vO  v5  CO  ^ 
00  vO  o  -*  o 


:!i  i  1 1  I  I  I  I  1 1 1 1 1 1  I  1 1 1 

^3 


I     O    O  vO 
rocO    « 

'       «M     1-1     (N 


ftfti  I  1^1  I  I  I  1  M 


in  be 


I      I    OnOn  I     ON  ON  C^   I 

do      odd 


O   M   ►^  ri- 

30    Tt  <M  CO 
30,00    ONOO 

6  6  6  6 


00  fO  o  vo 
ON  o^co  r>.  I 

d  d  d  d 


ON  M  t^  fO  cs 

On  OnCO  00  Cn 

d  vd  cJ  ro  d 


I  I 


VO  O 


C  3 
1-" 


M   O  HH   O   ►- 


1  I  I  I  I ::?  I 


OC^C'WMM'^fOT}- 


ONVO  rO  O  I-"  -^  O 
m'  >-<"  f<  d  (S  rO  i-< 


c  ~      -^  ri         10  ON 

Jj  8       O  »OvO  rOOi-;i-<tN"^OrO,  r--  OnvO  -  n  O 

00  CO  CO  00  00  00  00  00  JO  00  00    00  00  00  00  00  00  00 


o  o 


c 

sec 

0 

coo 

c 

S  S  E 

3 

3    3    3 

03 

<U 

OJ    OJ    (U 

WPQtt  m 

tn   t«   (fl   en 


•3.5 


CO    CO 
X   X 


cC   rt   cO   O 


X   X 


'w  tn 

t/)  3 

O  c/: 

^   ^  rt 

3   O  o 

^    >  3 

CO    O  CO 

n  t;; 'H  "ifi  'c«  *on 


CXI    ^   c«   05 
A»  i>   3   3 


S^  "tin 

(U4J»3q;Krj:<3=!5>3 


-^  o 
5  o 


472  ENGINEERING   CHEMISTRY 

Ultimate  Analysis  of  Oils.^ 

In  the  ultimate  analysis,  the  composition  of  the  oil  is  expressed 
in  percentages  of  carbon,  hydrogen,  nitrogen,  sulphur,  and  oxy- 
gen. Unfortunately,  there  is  no  simple  direct  method  for  the  de- 
termination of  oxygen  and  this  percentage  is  obtained  by  sub- 
tracting the  sum  of  the  other  percentages  from  lOO.  Hence,  this 
method  throws  the  algebraic  summation  of  all  the  errors  incident 
in  the  other  determinations  upon  the  oxygen.  The  determina- 
tion of  carbon,  hydrogen  and  nitrogen  requires  careful  manipula- 
tion and  a  considerable  degree  of  analytical  skill,  and  since  the 
errors  of  the  oxygen  determination  are  directly  dependent  upon 
the  errors  in  the  other  determinations  the  accuracy  of  these  de- 
terminations must  be  held  within  definite  limits  in  order  to  estab- 
lish a  degree  of  probable  accuracy  for  the  oxygen  determination. 
These  limits  follow :  carbon  0.3  per  cent. ;  hydrogen  0.07  per 
cent. ;  nitrogen  and  sulphur  0.05  per  cent. 

Carbon  and  Hydrogen  Determination. 

Carbon  and  hydrogen  are  determined  by  the  usual  method  of 
combustion  in  a  current  of  oxygen.  0.2  gram  sample  of  the  oil  is 
burned  in  a  25  burner  Bunsen  combustion  furnace,  the  purifying 
reagents  through  which  the  oxygen  is  led,  arranged  in  the  order 
named,  are  sulphuric  acid,  potassium  hydroxide,  soda  lime,  and 
granular  calcium  chloride.  The  combustion  tube  is  made  of  trans- 
parent fused  silica,  a  little  less  than  a  meter  in  length  and  about 
18  mm.  internal  diameter.  Complete  oxidation  is  insured  by 
passing  the  products  of  combustion  over  red  hot  copper  oxide. 
A  layer  of  lead  chromate  following  the  copper  oxide  removes  the 
sulphur. 

The  absorption  train  is  arranged  as  follows :  The  water  is  ab- 
sorbed in  a  100  millimeter  Schwartz  U-tube  filled  with  granular 
calcium  chloride.  The  carbon  dioxide  is  absorbed  by  potassium 
hydroxide  in  a  Vanier  combined  potash  bulb  and  drying  tube.  It 
is  well  to  interpose  a  tube  containing  a  solution  of  palladium 
chloride  with  a  calcium  chloride  guard  as  a  check  against  the  pos- 

^  Prepared  by  E-  G.  Bashore,  chief  chemist  of  the  Babcock  &  Wilcox  Company,  a 
standard  authority  on  the  subject. 


ENGINEERING   CHEMISTRY  473 

sibility  of  any  carbon  monoxide  passing  over  and  into  the  ab- 
sorption train.  Oils  must  of  necessity  be  distilled  over  very 
slowly  and  this  part  of  the  manipulation  is  governed  more  by  the 
experience  of  the  operator  than  any  hard  and  fast  rule  which  can 
be  laid  down. 

Nitrogen  Determination. 

Nitrogen  may  be  determined  by  the  Kjeldahl-Gunning  method. 
One  gram  of  the  sample  is  digested  with  50  cc.  of  concentrated 
sulphuric  acid,  0.65  gram  of  metallic  mercury,  and  5  grams  of 
potassium  sulphate,  until  the  carbon  has  been  completely  oxi- 
dized and  all  the  nitrogen  has  been  converted  to  ammonia  sul- 
phate. After  cooling,  the  solution  is  diluted  to  about  200  cc. 
with  cold  water.  The  mercury  is  percipitated  with  potassium 
sulphide  solution  (40  grams  KgS  per  liter)  and  about  2  grams  of 
granular  zinc  is  added  to  prevent  bumping.  The  solution  is  then 
made  distinctly  alkaline  through  the  addition  of  a  saturated  solu- 
tion of  sodium  hydroxide,  and  the  flask  is  immediately  con- 
nected with  the  condenser. 

The  ammonia  from  the  distillation  is  absorbed  in  10  cc.  of 
standard  sulphuric  acid,  i  cc.  of  which  is  equivalent  to  0.005 
gram  of  nitrogen.  The  residual  acid  is  titrated  with  standard 
ammonia  of  just  half  the  strength  of  the  acid  (i  cc.  equals  0.0025 
gram  of  nitrogen)  with  the  use  of  cochineal  as  the  indicator. 

The  method  of  Will  &  Varrentrapp  is  particularly  applicable 
for  the  nitrogen  determination  in  oils.  In  this  method  the  nitro- 
gen content  of  the  oil  is  converted  into  ammonia  by  heating  w4th 
soda-lime.  The  liberated  ammonia  is  led  through  a  standard  sul- 
phuric solution,  the  excess  of  which  is  titrated  with  standard 
alkali. 

A  glass  combustion  tube  closed  at  one  end  contains  at  the 
sealed  end  a  layer  of  oxalic  acid  or  calcium  oxalate  which  on 
heating  decomposes  with  evolution  of  carbon  monoxide  and  di- 
oxide. Next  to  this  is  the  weighed  sample  of  oil  mixed  with 
soda-lime  and  followed  by  a  third  layer  of  soda-lime  only,  the 
latter  held  in  place  by  an  asbestos  plug.  The  tube  is  connected 
with  a  bulb  containing  a  fixed  amount  of  standard  sulphuric  acid 


474  ENGINEERING   CHEMISTRY 

solution  of  which  i  cc.  is  equivalent  to  0.005  gram  of  nitrogen. 
The  combustion  is  carried  on  in  the  usual  way,  proceeding  to 
heat  the  tube  gradually  back  to  the  oxalic  acid.  When  the  gases 
from  the  decomposition  of  the  latter  have  completely  driven  out 
the  ammonia,  the  fixed  amount  of  standard  sulphuric  acid  (i  cc. 
equivalent  to  0.005  gram  of  nitrogen)  is  titrated  against  a  stand- 
ard solution  of  ammonia  of  just  half  the  strength  with  the  use  of 
cochineal  as  an  indicator. 

SuiyPHUR  Determination. 

A  quick  method  coupled  with  a  fair  degree  of  accuracy  con- 
sists in  determining  the  sulphur  from  the  "acid  correction"  in  the 
calorimeter  bomb  washings.  After  the  acid  correction  has  been 
applied,  the  insoluble  matter  is  filtered  off  and  washed  with  hot 
water.  The  filtrate  and  washings  which  should  have  a  total 
volume  of  about  200  cc.  are  acidulated  with  5  cc.  dilute  hydro- 
chloric acid  and  then  are  heated  to  boiling.  The  sulphur  is  pre- 
cipitated through  the  addition  of  20  cc.  of  a  hot  5  per  cent,  solu- 
tion of  barium  chloride. 

The  results  obtained  by  this  method  are  usually  somewhat  low 
due  to  loss  of  sulphur  trioxide  in  the  gas  escaping  from  the 
bomb.  On  the  other  hand,  the  method  has  the  advantage  of  ef- 
fecting a  material  saving  in  time. 

Sulphur  may  be  determined  by  the  longer  and  more  accurate 
Eschka  method.  One  gram  of  the  sample  is  mixed  in  a  platinum 
crucible  with  about  2  grams  of  the  "Eschka  mixture"  (i  part 
anhydrous  sodium  carbonate  and  2  parts  calcined  magnesium  ox- 
ide). About  I  gram  of  the  mixture  is  placed  over  the  top  to  form 
a  cover.  It  is  necessary  to  have  a  blank  on  the  sulphur  content 
of  the  Eschka  mixture.  The  ignition  is  first  started  with  a  very 
low  flame  and  it  is  preferable  to  use  alcohol  or  natural  gas  flame. 
Artificial  gas  often  contains  so  much  sulphur  that  its  use  may 
introduce  an  error  into  the  determination. 

After  the  crucible  has  been  heated  very  slowly  and  cautiously, 
the  heat  is  gradually  increased  until  the  crucible  and  its  contents 
become  red  hot.  The  contents  of  the  crucible  are  heated  with  oc- 
casional  stirring  until   all   the   black   particles   are   burned   out. 


e)ngine:ering  chemistry  475 

After  cooling  the  contents  of  the  crucible  are  transferred  to  a 
200  cc.  beaker  and  digested  with  75  cc.  of  hot  water  for  about  30 
minutes.  The  solution  is  then  filtered,  the  residue  washed  twice 
with  hot  water  by  decantation  and  then  washed  on  the  filter, 
small  portions  of  water  being  used  for  each  washing  till  the 
filtrate  amounts  to  about  200  cc.  Five  cc.  of  bromine  water  is 
then  added  and  the  solution  is  made  slightly  acid  with  5  cc.  dilute 
hydrochloric  acid.  The  solution  is  heated  to  boiling,  and  the 
sulphur  is  precipitated  as  barium  sulphate  with  the  addition  of 
20  cc.  of  a  hot  5  per  cent,  solution  of  barium  chloride.  The  pre- 
cipitate is  allowed  to  stand  at  a  temperature  a  little  below  boil- 
ing for  at  least  2  hours  before  filtering.  After  careful  ignition 
to  dull  redness  in  an  excess  of  air  the  crucible  and  precipitate  are 
cooled  and  weighed. 


SOAP  ANALYSIS. 

Soaps  may  be  conveniently  classified  into — 

Toilet  soaps,  the  finest  grades  of  which  contain  no  impurities 
or  free  alkali; 

Laundry  soaps,  in  which  tallow  is  present  and  generally  an  ex- 
cess of  alkali  either  as  sodium  silicate,  sodium  carbonate,  sodium 
borate,  or  free  alkali; 

Commercial  soaps,  which  may  be  subdivided  into  (a)  soft 
soaps,  potash  being  the  base,  and  (b)  "hydrated"  soaps,  soda 
being  the  base  ("marine  soap"  being  an  example,  formed  by 
caustic  soda  and  palmnut  oil  or  cocoanut  oil)  ; 

Resin  soaps,  in  which  resin  is  present  and  an  excess  of  alkali, 
with  tallow,  etc. ;  and 

Medicated  soaps,  containing  medicinal  agents  such  as  carbolic 
acid,  tar,  sulphur,  etc.,  etc. 

The  complete  analysis  of  a  soap  often  presents  considerable 
difficulty — since  many  adulterants  may  be  used  in  the  cheaper 
grades,  and  many  substances  not  adulterants,  the  use  of  which  is 
permitted  as  colorants  and  for  perfume.     Allen  states  that  be- 


476  ENGINEERING   CHEMISTRY 

sides  the  alkali  and  fatty  acids  and  water  requisite  for  the  forma- 
tion of  a  soap,  the  following  substances  have  been  found  in  the 
different  varieties — ochre,  ultramarine,  sodium  aluminate,  borax, 
resin,  vermilion,  arsenite  of  copper,  alcohol,  sugar,  vaseline,  cam- 
phor, gelatin,  petroleum,  naphthalene  and  creosote  oils  carbolic 
acid,  tar,  glycerine  in  excess,  oatmeal,  bran,  starch,  barium  sul- 
phate, sulphur,  steatite,  clay.  Fuller's  earth,  pumice  stone,  kie- 
selguhr,  chalk  whiting,  etc. 

The  common  ''yellow  soap"  is  formed  by  the  combination  of 
tallow  or  palm  tree  oil  or  resin  with  soda;  "recovered  grease" 
is  also  used  in  the  cheaper  grades;  cotton  seed  oil,  olive  oil, 
hemp-seed  oil,  palm  oil,  cocoanut  oil,  castor  oil,  lard,  and  lard  oil, 
are  all  used  in  the  manufacture  of  various  soaps. 

The  scheme  for  soap  analysis  is  by  A.  R.  Leeds,  Ph.D. 

Water. 

For  the  determination  of  water,  the  method  of  Lowe  is  often 
employed. 

From  8  to  lo  grams  of  the  soap  (which  has  been  reduced  to 
very  fine  shavings,  and  represents  an  average  sample)  are 
weighed  out  between  watch  glasses  and  heated  in  the  air-bath,  at 
first  from  6o°-70°  C.  to  avoid  melting,  then  at  ioo°-i05°  C.  to 
constant  weight.  In  selecting  the  sample  in  this,  as  well  as  in  all 
subsequent  determinations,  it  is  essential  that  an  average  speci- 
men be  obtained,  since  the  content  of  water  in  the  different  parts 
of  the  bar  varies  considerably. 

This  is  best  effected  by  cutting  away  about  one-third  from  the 
end  and  evenly  scraping  the  cut  surface  of  the  remainder  until  a 
sufficient  amount  is  obtained  for  analysis. 

If  the  determination  of  free  alkali  is  of  considerable  impor- 
tance the  soap  should  be  dried  in  an  atmosphere  free  from  car- 
bon dioxide.  The  loss  at  105°  C.  represents  the  water  together 
with  other  volatile  constituents,  such  as  alcohol  and  essential  oils, 
which  may  be  present. 


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e:ngine:e:ring  che:mistry  479 

Method  of  K.  Brown  for  Free  Water  and  Alkali  in  Soap.^ 

Weigh  the  sample  of  the  finely  divided  soap  into  a  wide  neck 
flask,  fitted  with  a  U-tube  filled  with  granulated  soda  lime,  and 
dry  to  constant  weight.  The  loss  represents  the  water,  and  the 
soda  lime  tube  prevents  the  access  of  carbonic  dioxide  of  the  air 
and  consequent  conversion  of  the  free  alkali  into  carbonate  dur- 
ing drying.  The  dried  soap  is  then  dissolved  in  the  smallest 
quantity  of  alcohol  possible  and  the  alkali  determined,  as  usual, 
by  titration  with  standard  acid  using  phenolphthalein  as  indi- 
cator. 

Unsaponified  Matter. 

For  the  determination  of  unsaponified  matter^  the  soap,  which 
has  been  dried  in  the  manner  indicated,  is  extracted  in  a  Soxhlet 
extraction  apparatus  with  petroleum  ether,  which,  for  this  pur- 
pose, should  boil  below  80°  C,  and  should  leave  no  residue  upon 
evaporation.  After  the  extraction  is  complete,  the  petroleum 
ether  is  distilled  off,  the  residue  dried  at  100°  C.  and  weighed. 
In  a  boiled,  well-made  laundry  soap,  there  should  be  no  unsa- 
ponified matter. 

In  addition  to  unsaponified  fats,  foreign  matters  are  sometimes 
found  in  the  petroleum  ether  extract,  such  as  a  soft  paraffine 
(so  called  "Mineral  Soap  Stock"),  waxes,  hydrocarbon  oils, 
phenol,  etc.  If  waxes  are  found  to  be  present,  the  dried  soap 
should  be  extracted  with  boiling  toluene,  which  dissolves  the 
same  better  than  petroleum  ether. 

Total  Alkali.    Fatty  Acids. 

The  dried  soap  thus  freed  from  unsaponified  matter  is  next 
dissolved  in  hot  water,  preparatory  to  determining  the  total 
alkali  and  fatty  acids.  A  pure  soap  dissolves  completely  in  hot 
water,  and  no  ordinary  product  should  leave  more  than  a  slight 
residue.  If  the  article  examined  is  a  ''scouring  soap,"  the  in- 
soluble residue  will  be  found  to  contain  quantities  of  fine  sand 

'^  Angew.  Chemie.,   i8,  p.   573. 

2  Allen's  "Commercial  Organic  Analysis,"  Vol.  II. 


480  DNGINDERING   CHEMISTRY 

and  sometimes  talc.  The  residue,  if  appreciable,  should  be 
washed  by  decantation,  and  eventually  brought  upon  a  filter  with 
hot  water,  dried  at  100°  C,  and  weighed,  after  which,  if  desired, 
it  can  be  subjected  to  further  examination. 

To  the  aqueous  solution  is  added  an  excess  of  half-normal  sul- 
phuric acid  setting  free  the  fatty  acids  which  rise  to  the  surface. 
The  beaker  or  vessel  in  which  the  precipitation  was  effected  is 
next  cooled  with  ice  water.  When  the  fatty  acids^  have  solidi- 
fied, it  is  best  to  decant  the  liquid,  remelt  with  water  two  or 
three  times  to  remove  any  enclosed  mineral  acid,  again  cool,  filter, 
and  wash  with  cold  water  until  the  washings  are  no  longer  acid, 
as  shown  by  litmus. 

The  filtrate  from  the  insoluble  fatty  acids  contains  the  total 
alkali  now  present  as  sulphate,  the  excess  of  sulphuric  acid  and 
any  glycerol  which  may  have  been  present  in  the  soap,  if  saponi- 
fication was  effected  in  the  cold.  The  acid  liquid  may  further 
contain  a  small  amount  of  soluble  fatty  acids.  It  is  first  titrated 
with  half-normal  potassium  hydroxide  using  methyl  orange  as 
indicator.-  From  the  original  amount  of  sulphuric  acid  added 
and  the  number  of  cubic  centimeters  half-normal  potassium  hy- 
droxide required  to  neutralize  the  excess  of  the  same,  the  total 
alkali  of  the  sample  can  be  determined. 

It  is  calculated  to  Na^O.  After  the  liquid  has  been  rendered 
neutral  to  methyl  orange  (which  indicates  the  mineral  acid), 
phenolphthalein  is  added  and  more  potassium  hydroxide  is  run 
in.  The  number  of  cubic  centimeters  of  potassium  hydroxide  re- 
quired for  neutralizing  to  phenolphthalein  corresponds  to  soluble 

in  the  absence  of  more  definite  knowledge  as  to  their  nature. 
The  solution  is  now  concentrated  and  tested  for  glycerol,  which 
may  be  determined  by   evaporating  to   dryness   and   extracting 

^  Bulletin  No.  13,  Pt.  4,  p.  456,  U.  S.  Department  of  Agriculture,  Chemical  Division. 
^AJlen's  "Commercial  Organic  Analysis,"  Vol.  II,  p.  260. 


ENGINEERING    CHEMISTRY  481 

with  ether  alcohol  mixture/  or  else  by  oxidizing  to  oxalic  acid  by 
means  of  permanganate^   (not  always  applicable).^ 

In  soaps  containing  silicates  of  the  alkalies  (a  not  unusual  con- 
stituent), the  gelatinous  silicic  acid  which  separates  on  the  addi- 
tion of  sulphuric  acid  remains  with  the  fatty  acids  on  filtration. 
To  separate  the  fatty  acids  from  this  as  well  as  other  impurities, 
proceed  as  follows : 

The  funnel  containing  the  filter  with  the  fatty  acids  is  placed 
in  a  small  beaker  and  heated  in  an  air-bath  (Allen's  method). 
As  the  filter  dries,  the  fatty  acids  pass  through  it  and  collect  in 
the  beaker  below,  while  all  impurities  (silicic  acid,  talc,  etc.)  re- 
main on  the  filter.  Of  course,  it  is  necessary  to  wash  the  filter, 
which  remains  saturated  with  the  fatty  acids,  with  hot  redistilled 
alcohol  or  petroleum  ether,  or  else  exhaust  in  an  extraction  appa- 
ratus. The  alcohol  or  petroleum  ether  is  distilled  off  and  the 
residue  treated  in  the  same  way  as  the  main  quantity  of  fatty 
acids. 

In  determining  the  fatty  acids  in  a  soap,  it  is  frequently  con- 
venient to  extract  with  ether  in  a  separatory  funnel.*  To  do  this 
the  soap  solution  is  placed  in  the  funnel  and  shaken  with  dilute 
sulphuric  acid  and  ether.  The  separated  acids  are  at  once  dis- 
solved in  the  ether.  The  aqueous  solution  may  be  drawn  off  be- 
low, the  ethereal  solution  washed  with  water,  the  ether  evapor- 
ated, and  the  residue  dried  at  ioo°  C,  and  weighed. 

Since  the  fatty  acids  exist  in  the  soap  as  anhydrides  and  are 
weighed  as  hydrates,  it  is  necessary  to  multiply  the  weight  found 
by  the  factor  0.97,  which  gives  the  weight  of  fatty  anhydrides. 
The  fatty  acids,  after  having  been  weighed,  may  be  titrated  with 
half -normal  potassium  hydroxide,  and  from  these  data  may  be 
ascertained  what  portion  of  the  total  alkali  exists  in  combination 
with  the  fatty  acids  as  soap. 

1  Chem.  Ztg  ,  8,  1667. 
-  Ibid,  9,  975. 

'  Allen's  "Commercial  Organic  Analysis,"  Vol.  II,  p.  290. 
*  Chem.  News,  43,  218. 
31 


482  ENGINEERING   CHEMISTRY 

Free  Alkali.^ 
To  determine  the  per  cent,  of  free  alkali-  in  soap,  a  separate 
portion  is  weighed  out  and  extracted  with  neutral  alcohol  in  an 
extraction  apparatus.  The  caustic  alkali  is  determined  in  the 
alcoholic  solution  by  titrating  with  half -normal  hydrochloric  acid, 
using  phenolphthalein  as  indicator.  If,  however,  the  soap  con- 
tains unsaponified  fat,  as  is  frequently  the  case  if  made  by  the 
so-called  "cold-process,"  this  method  cannot  be  used,  since  in 
alcoholic  solution  unsaponified  fat  would  be  readily  saponified  by 
the  free  caustic  alkali  present.  In  such  a  case  the  soap  must  first 
be  dried  in  an  atmosphere  free  from  carbon  dioxide  at  100°  C, 
the  unsaponified  matter  extracted  with  petroleum  ether,  and 
finally  the  soap  dissolved  in  alcohol  and  the  free  alkali  deter- 
mined in  the  alcoholic  solution  as  before. 

Carbonated  Alkali. 

The  sodium  carbonate,  sodium  silicate,  borax,  and  everything 
insoluble  in  alcohol,  remains  behind  in  the  extraction  tube  and 
may  be  dried  at  100°  C.  and  weighed.  If  considerable,  it  may  be 
further  treated,  as  follows : 

First,  it  should  be  exhausted  with  boiling  water;  one-half  of 
this  solution  is  then  titrated  with  half -normal  hydrochloric  acid 
using  methyl  orange  as  indicator.  The  amount  of  acid  required 
corresponds  to  carbonate,  silicate,  and  borate.  In  this  solution 
sulphates  may  also  be  determined  and  starch  and  gelatine  tested 
for.  The  other  half  of  the  solution  is  examined  qualitatively  for 
carbonate,  silicate,  and  borate.  If  there  remains  a  considerable 
residue  insoluble  in  water,  it  may  be  dried  at  100°  C,  weighed 
and  further  examined. 

Resin. 

Resin  is  a  very  common  constituent  of  soaps,  the  resinates  of 
the  alkalies  having  an  action  similar  to  soaps,  and  the  cheapness 
of  the  material  often  suggesting  a  partial  substitution  of  it  for 
the  natural  fats  and  oils. 

^  Consult  "Method  for  the  Estimation  of  the  Total  Alkali,  the  Free  Alkali  and  the 
Carbonated  Alkali  in  Soaps,"  by  R.  Henriques  and  O.  Meyer,  Chemical  News,  April 
18,    1902. 

^Allen's  "Commercial  Organic  Analysis,"  Vol.  II,  p.  251. 


ENGINEERING   CHEMISTRY  483 

As  a  qualitative  test  for  resin,  Gottlieb's^  method  is  reliable 
and  easily  made. 

The  soap  is  dissolved  in  water  and  heated  to  boiling.  A  strong 
solution  of  magnesium  sulphate  is  added  until  the  fatty  acids  are 
completely  precipitated.  The  magnesium  resinates  remain  in  so- 
lution. After  boiling  2  or  3  minutes,  the  solution  is  filtered 
and  the  hot  filtrate  acidified  with  dilute  sulphuric  acid.  In  the 
presence  of  resin  the  liquid  becomes  turbid,  due  to  the  separated 
resin  acids.  The  boiling  should  be  continued  for  Yz  hour,  to 
make  sure  that  the  turbidity  is  due  to  resin  acids  and  not .  to 
volatile  fatty  acids.  One  method  for  the  quantitative  determina- 
tion of  resin  in  soap  is  that  of  Hiibl,^  as  follows : 

From  0.5  to  i  gram  of  the  mixture  of  fatty  and  resin  acids  is 
heated  in  a  closed  flask  on  the  water  bath  with  about  20  cc.  of 
alcohol  to  complete  solution.  The  acids  are  neutralized  with  al- 
kali, using  phenolphthalein  as  indicator.  The  alcohol  soap  so- 
lution is  then  poured  into  a  beaker,  the  flask  rinsed  with  water, 
the  solution  diluted  to  200  cc,  and  silver  nitrate  added  to  com- 
plete precipitation.  The  precipitate  (consisting  of  the  silver  salts 
of  the  resin  and  fatty  acids)  must  be  protected  from  sunlight.  It 
is  filtered,  washed  with  water  at  100°  C,  and  extracted  in  a 
Soxhlet  tube  with  ether.  The  silver  resinates  dissolve  in  the 
ether,  while  the  silver  salts  of  the  fatty  acids  remain  behind.  The 
ethereal  solution,  as  it  leaves  the  extraction  tube,  should  be  yel- 
low or  light  brown  in  color,  but  not  dark  brown.  It  is  filtered, 
if  necessary,  and  the  filtrate  shaken  with  hydrochloric  acid  in  a 
separatory  funnel.  The  resulting  ethereal  solution  of  the  resin 
acids  is  filtered  from  the  silver  chloride,  washed  with  water,  and 
the  filter  and  separator  rinsed  with  ether,  the  ether  distilled  off, 
and  the  residue  dried  at  100°  C.  As  the  resin  is  weighed  in  the 
hydrated  form,  its  weight  must  be  multiplied  by  the  factor  0.9732 
to  obtain  the  weight  of  the  anhydride. 

Twitchell's  method  for  the  determination  of  resin  in  a  mix- 
ture with  fatty  acids  depends  upon  the  formation  (in  alcoholic 
solution)   of  the  ethereal  salts  of  the  latter  when  treated  with 

1  Benedikt's  "Analyse  der  Fette  u.  Wachsarten,"  p.    121. 

2  Benedikt's  "Analyse  der  Fette  u.  Wachsarten,"  p.    125. 


484  ENGINEERING   CHEMISTRY 

hydrochloric  acid,  resin  being  unacted  upon.     The  gravimetric 
method  is  as  follows : 

Two  or  3  grams  of  the  mixture  of  fatty  acids  and  resin 
are  dissolved  in  ten  times  their  volume  of  absolute  alcohol  and 
dry  hydrogen  chloride  is  passed  through  in  a  moderate  stream, 
the  flask  being  placed  in  a  vessel  with  water  to  keep  it  cool.  The 
gas  is  rapidly  absorbed,  and  after  about  45  minutes  the 
ethereal  salts  separate  and  float  on  the  solution.  After  waiting 
Yz  hour  longer,  the  liquid  is  diluted  with  five  times  its  bulk 
of  water  and  boiled  until  the  acid  solution  is  clear,  the  ethereal 
salts,  with  resin  in  solution,  floating  on  top.  To  this  is 
added  some  light  petroleum,  and  the  whole  transferred  to  a 
separatory  funnel,  the  flask  being  washed  out  with  light  petro- 
leum. The  acid  liquid  is  then  run  off,  and  the  petroleum  ether 
solution  washed  once  more  with  water  and  then  treated  in  the 
funnel  with  a  solution  of  0.5  gram  of  potassium  hydroxide  and  5 
cc.  of  alcohol  in  50  cc.  of  water.  The  resin  is  immediately  saponi- 
fied, and  the  two  layers  separate  completely.  The  resin  soap  solu- 
tion can  then  be  run  off,  and  the  resin  recovered,  as  usual,  by  the 
addition  of  an  acid.  The  first  stages  of  the  volumetric  method 
are  similar  to  those  of  the  gravimetric,  with  the  exception  that  the 
contents  of  the  flask  are  washed  into  the  separating  funnel  with 
ether  instead  of  light  petroleum,  and  the  ethereal  solution  is  then 
thoroughly  washed  with  water  until  all  soluble  acidity  is  re- 
moved; 50  cc.  of  neutral  alcohol  are  then  added,  and  the  solution 
titrated  with  standard  solution  of  sodium  hydroxide. 

It  is  frequently  of  interest  to  know  the  origin  of  the  fatty  acids 
of  a  soap  which  is,  however,  in  many  cases,  a  problem  not  easily 
solved.  The  only  clues  are  to  be  sought  in  the  specific  gravity, 
combining  weight,  melting-  and  solidifying-points  and  iodine 
number  of  the  fatty  acids. 

The  values  for  the  specific  gravities  in  column  III,  page  485, 
were  obtained  with  a  Westphal  and  a  Reiman's  balance  plum- 
met, with  a  thermometer  of  a  range  95°- 101°  C. 

Occasionally,  fats,  before  being  used  in  soap  making,  are 
bleached  by  various  chemical  agents,   the  most  common  of   which 


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486  ENGINEE)RING   CHEMISTRY 

are,  perhaps,  potassium  dichromate  and  hydrochloric  acid,  or  sul- 
phuric acid.  If  now  such  a  mixture  is  heated  in  bleaching,  as  is 
frequently  the  case,  the  potassium  dichromate  acting  on  the  hy- 
.drochloric  acid  liberates  chlorine,  and  under  favorable  condi- 
tions, the  chlorine  combines  with  the  unsaturated  acids  present  in 
the  fats  as  glycerides,  thus  utterly  destroying  the  value  of  the 
iodine  number,  the  most  definite  index  as  to  the  origin  of  the  fats. 
Again  it  frequently  occurs  that  a  mixture  of  two  or  more  fats 
may  be  used,  the  combining  weights,  iodine  number,  and  other 
properties  of  which  closely  approximate  those  of  an  individual 
fat,  and  so  an  erroneous  conclusion  may  be  drawn  from  an  exami- 
nation of  such  mixed  fatty  acids.  If,  however,  a  mixture  of  two 
fats,  in  their  natural  state,  without  having  undergone  any  bleach- 
ing or  refining  process,  is  used,  it  is  generally  possible  to  ascer- 
tain, with  considerable  accuracy  the  nature  of  the  fatty  acids  by 
means  of  the  iodine  number,  it  having  been  found  by  actual  ex- 
periment that  the  iodine  number  of  a  mixture  of  two  fats  corre- 
sponds within  limits  of  analytical  error  with  the  theoretical  num- 
bers calculated  for   the  pure  fats. 

Grlycerine  in  Fats  and  Soaps 

can  be  determined  as  follows  :^  Three  grams  are  saponified  with 
an  alcoholic  potash  solution,  the  soap  solution  diluted  to  200  cc. 
decomposed  with  dilute  acid,  filtered  from  insoluble  fatty  acids, 
and  the  filtrate  and  washings,  which  should  amount  to  above  500 
cc.  evaporated  rapidly  down  to  250  cc,  sulphuric  acid  added  and 
titrated  with  standard  potassium  bichromate. 

For  titration  by  bichromate  the  following  solutions  are  re- 
quired : 

1.  Bichromate  solution  containing  about  74.86  grams  of  potas- 
sium bichromate  and  150  cc.  strong  sulphuric  acid  per  liter.  The 
oxidizing  value  of  the  solution  must  be  ascertained  by  titration 
with  solutions  containing  known  amounts  of  iron  wire. 

2.  Ferrous  ammonium  sulphate  solution  containing  about  240 
grams  per  liter. 

1  O.  Hehner  :  J.  Soc.  Chem.  Ind.,  8,  4. 


ENGINEERING    CHEMISTRY 


487 


3.  A  bichromate  solution  one-tenth  as  strong  as  the  first.  The 
ferrous  solution  is  standardized  upon  the  chromate  solution,  and 
the  glycerol  value  of  the  chromate  (contents  of  bichromate 
divided  by  7486)  is  calculated.  One  and  five-tenths  grams  of 
the  glycerol  or  soap  lye  are  weighed  into  a  100  cc.  flask,  and  a 
little  silver  oxide  added  to  remove  any  chlorine  or  aldehyde  com- 
pounds. After  slight  dilution,  the  sample  is  allowed  to  stand 
with  the  silver  oxide  for  about  10  minutes.  Basic  lead  acetate  is 
then  added  in  slight  excess,  the  bulk  of  the  liquid  made  up  to 
100  cc.  and  a  portion  filtered  through  a  dry  filter. 

Twenty-five  cubic  centimeters  of  the  filtrate  are  placed  in  a 
clean  beaker,  then  40  to  50  cc.  of  the  standard  bichromate  solu- 
tion accurately  measured,  are  added,  and  15  cc.  strong  sulphuric 
acid.  The  beaker  is  covered  with  a  watch  glass  and  heated  for 
2  hours  in  boiling  water.  The  excess  of  bichromate  solution  is 
then  titrated  back  with  the  ferrous  ammonium  sulphate  solution 

The  following  table  of  analyses  of  soaps  comprise  in  each  in- 
stance a  complete  analysis : 


Anai^ysis  of  Soaps. 

8 

P 

s 

1 

0 

1 

c 

1 

U  <u 

0  X 

'.3 

Description 
of  soap 

Origin 

'm 

(A 

CO 

1 

1 

E 

'•5 

B 

*  to 

«.5 

s 

rt 

.2-0 

5 

s 

4,'0 

V 

"rt 

^1 

o.£ 

•g 

"Bg 

1 

"o 

.£§ 

1 

0 

rtS 

fa 

Cfi'" 

cfl 

tn 

Cfi 

tfl 

en 

J 

f- 

fa 

"White  No.  1.  .   . 

Tallow  .... 

69.06 

8.,8 

O.OI 

none 

0.27 

0,49 

0.16 

0.07 

21.14 

100.18 

71.20 

White  No.  2  .   .   . 

f  Tallow  and") 

( cocoan't  oil  j 

Tallow. 

60.50 

6.82 

0.06 

none 

0.96 

O.ll 

0.12 

0.16 

32.30 

100.13 

62.36 

Cold  water  .  . 

J    resin  and 
1  cotton  seed 
I         oil 

71-30 

7.98 

1.07 

0.48 

0.75 

0.36 

0.30 

0.16 

17.44 

99.84 

73-50 

Palm  oil    .   .   .   . 

Palm  oil.  .   .   . 

59.28 

6.65 

0.42 

o.oi 

0.39 

0.47 

0.13 

o.r6 

32.35 

99.86 

•Si. 08 

Olive  oil  No.  i.  . 

Olive  oil    ... 

71.20 

7.58 

0.06 

0.03 

0.22 

0.66 

0.17 

0.20 

19  70 

99.82 

73-40 

Pale  resin  No.  i. 

J  Tallow  and) 
(        resin       J 
( Tallow  and  I 
\        resin        J 
Palm  nut  oil 

60.90 

7.22 

0.04 

none 

O.IO 

0.46 

0.12 

0.02 

31-22 

100.08 

62.78 

Pale  resin  No.  3. 

39-92 

4.70 

0  62 

0.25 

0.20 

1.48 

0.18 

0.15 

52.40 

99.90 

41-15 

Marine 

19.42 

3-II 

9.00 

3.98 

3.00 

5-13 

0.35 

o.ib. 

53-32 

97-47 

20.02 

"White  ca.stile  .  . 

76-7 

9-M 

~ 

0.09 

0.36 

~ 

0.09 

13-25 

10054 

~ 

In  most  analyses  of  soaps  the  following  determinations  only 
are  made:  Water,  alkali  combined  as  soap  (Na20),  alkali  free 
as  sodium  hydroxide,  sodium  carbonate,  and  total  fatty  acids  as 


488  ENGINEERING   CHEMISTRY 

anhydrides.    Thus,  an  ordinary  yellow  laundry  soap,  analyzed  by 
Schnaible,  gave : 

Per  cent. 

Water   19.02 

Alkali,  combined  as  soap,  Na20 8.57 

Alkali  free,  as  NaOH 0.20 

Alkali,  Na^CO, 0.20 

Insoluble  in  H2O 0.24 

Fatty  anhydrides  52.32 

Resin  1945 

Total     100.00 

Specifications  for  Laundry  and  Toilet  Soap,  Issued  by  the  Bureau  of 
Supplies  and  Accounts,  Navy  Department,  January,  1908. 

Soap  {Laundry) .—Mwst  not  contain  more  than  25  per  cent,  of  resin; 
not  more  than  one-half  of  i  per  cent,  of  free  alkali  (NaOH)  ;  not  more 
than  one  half  of  i  per  cent,  of  mineral  matter ;  not  more  than  one-half  of 
I  per  cent.  of*free  carbonated  alkali  (Na2C03),  and  not  more  than  28 
per  cent,  of  water ;  the  balance  to  be  strictly  neutral,  hard  tallow  soap. 

Soap  {Toilet). — To  be  milled,  neutral,  soda  soap,  made  from  clean, 
wholesome  fat,  and  as  free  as  possible  from  water,  resin  and  mineral, 
starchy,  or  foreign  material.  Analysis  must  show  not  more  than  three- 
tenths  of  I  per  cent,  of  mineral  matter,  three-tenths  of  i  per  cent,  of  car- 
bonated alkali,  calculated  as  carbonate  of  soda  (Na2C03),  one-half  of  i 
per  cent,  of  uncombined  alkali,  calculated  as  caustic  soda  (NaOH),  i  per 
cent,  of  common  salt,  or  14  per  cent,  of  water.  A  cylinder  of  soap  %  inch 
in  diameter  and  i  inch  high  cut  from  a  cake  must  sustain  a  weight  of 
15  pounds  for  5  minutes  without  crushing  or  compressing  more  than 
1/16  inch.  Soap  will  be  rejected  if  made  so  largely  of  cocoanut  oil,  palm 
oil,  or  other  fat  of  characteristic  smell  that  the  peculiar  odor  remains  on 
the  hands  after  using.  To  be  perfumed  with  the  characteristic  odor  of 
lavender ;  perfume  to  add  not  more  than  5  cents  per  pound  to  the  cost 
of  the  soap. 

Cakes  to  be  oval,  to  weigh  about  4  ounces ;  color,  light  brown.  Each 
cake  to  be  wrapped  in  soft  paper ;  to  be  packed  in  neat  paper  boxes, 
three  cakes  to  a  box. 

The  soap  will  be  bought  by  the  pound. 

For  inspection,  one  cake  taken  at  random  will  be  examined,  and  the 
lot  will  be  accepted  or  rejected  on  this  sample  cake. 

The  weight  of  the  soap  to  be  paid  for  will  be  determined  by  the 
amount  of  combined  alkali  or  its  equivalent  in  the  lot;  this  to  be  found 
by   multiplying  the   weight   in   grains   of   combined   alkaU   in   the   sample 


ENGINEERING    CHEMISTRY  489 

cake  by  the  number  of  cakes,  then  dividing  this  product  by  630,  the 
number  o£  grains  of  combined  alkaU  assumed  as  a  standard  pound  of 
soap. 

Specifications  for  Castile  Soap  (1908). 

To  be  neutral  soda  soap  made  from  pure  oHve  oil.  It  must  be  of 
good  color,  devoid  of  rancid  odor,  and  free  from  uncombined  oil,  fats, 
resin,  mineral  and  starchy  matter,  and  all  other  foreign  materials  or 
fillers.     The  analysis  must  show : 

1.  Uncombined  alkali  (caustic  soda  NaOH,  and  sodium  carbonate 
Na2C03),  not  more  than  0.25  per  cent. 

2.  Mineral  matter,  including  sihca,  sulphate  of  soda,  etc.,  not  more 
than  0.3  per  cent. 

3.  Salt  (NaCl),  not  more  than  i  per  cent. 

4.  Moisture,  not  more  than  28  per  cent. 

5.  The  balance  to  be  neutral  soap  made  from  pure  olive  oil. 
The  soap  to  be  delivered  in  4-pound  bars. 

Specifications  for  Salt  Water  Soap  (1909). 

Must  be  well  made  from  pure  cocoanut  oil  and  the  necessary  alkalies 
only.  Must  be  entirely  soluble  in  both  sea  water  and  fresh  water  and 
make  a  good  lather  in  using,  and  must  be  free  from  fillers  of  any  kind. 
When  received,  the  bars  shall  weigh  3  avoirdupois  pounds  each  and  shall 
contain : 

Carbonated  alkali   (equivalent  to  Na2C03),  between  2  and  3  per  cent. 

Free  alkaH   (equivalent  to  NaOH),  not  more  than  0.50  per  cent. 

Salt  (NaCl),  not  more  than  3  per  cent. 

Mineral  matter,  including  silicate  of  soda,  sulphate  of  soda,  etc.,  not 
more  than  0.50  per  cent. 

Water,  not  more  than  55  per  cent. 

Balance  to  consist  exclusively  of  cocoanut  oil  combined  with  the 
proper  amount  of  alkali  to  form  a  neutral  soap. 

The  soap  shall  be  delivered  in  strong  wooden  boxes  holding  75  pounds 
each,  strapped  with  iron  at  each  end.  The  box  shall  be  made  of  No,  i 
box  lumber  and  marked  with  the  weight,  name  of  contractor,  date  of 
purchase,  and  on  each  end  of  the  box  "Bureau  of  Equipment"  or  "Supplies 
and  Accounts,"  as  may  be  specified. 

The  soap  and  boxes  shall  conform  to  the  standard  sample  at  the  equip- 
ment department  or  general  storekeeper's  oflice.  Navy  Yard,  New  York. 

Transparent  soaps   are   obtained   by   dissolving  the   soaps    in 
alcohol  and  drying  the  solutions  in  moulds — a  slow^  process.^ 

^  A  very   complete    article   upon   the   properties    and   manufacture    of    "Transparent 
Soaps"  is  by  W.  D.  Richardson,  Jour.  Amer.   Chetn.   Soc,  March,   1908,  pp.  414-420. 


490  DNGINKDRING    CHEMISTRY 

Glycerine  soaps  are  obtained  by  dissolving  the  soaps  jn  glycer- 
ine by  the  aid  of  heat.  The  glycerine  imparts  a  strength  to  the 
lather. 

Washing  Powders. 

The  washing  or  soap  powders  contain  besides  powdered  soap, 
a  large  percentage  of  sodium  carbonate,  usually  in  the  form  of 
dried  soda  crystals.  These  powders  are  generally  prepared  as 
follows :  Anhydrous  sodium  carbonate  or  anhydrous  soda  ash  is 
added  to  a  ''clear  boiled"  soap  paste,  and  after  thoroughly  mix- 
ing, the  somewhat  stiff  material  is  drawn  off  into  cooling  frames.^ 
The  cold  and  hard  soap  thus  formed  is  then  finely  ground.- 

The  composition  varies  greatly.  Only  a  small  proportion  of 
resin  soap  can  be  used,  as  such  a  soap  is  sticky  and  cannot  be 
powdered. 

Olein  soap  is  generally  used  and  is  saponified  with  sodium  car- 
bonate. 

Specifications  for  Soap  Powder  (1906). 

1.  The  soap  powder  to  be  a  uniform  mixture  of  soap  and  soda  ash, 
in  powdered  or  granular  form.  To  be  freely  soluble  in  luke-warm  water; 
and  show  on  analyses  not  less  than  25  per  cent,  of  anhydrous  soap,  not 
less  than  45  per  cent,  of  dry  sodium  carbonate  (Na2C03),  and  not  more 
than  20  per  cent,  of  moisture.  To  be  free  from  resin,  caustic  alkali,  and 
all  inert  fillers. 

2.  It  shall  be  delivered  in  rectangular  cartons  containing  not  more 
than  4  pounds  net  of  soap  powder.  The  weight  of  the  cartons,  packing, 
etc.,  will  not  be  included  in  weight  of  soap  powder  constituting  a  delivery. 

English  Patent,  Nov.  14,  1907,  for  a  soap  powder,  describes  a 
method  of  manufacture  as  follows :  "A  very  dry  soap  powder 
free  from  cakes  or  lumps,  is  obtained  by  introducing  steam  into 
a  vessel  containing  liquid  soap,  below  the  level  of  the  liquid, 
thereby  heating  the  liquid  to  the  temperature  of  the  steam,  and 
then  blowing  the  hot  liquid  soap  out  of  the  vessel  into  a  chamber 
where  the  powder  is  deposited,  while  continuously  maintaining 
the  pressure  of  the  steam  at  the  same  height." 

^  Chem.  Zeit.,   1893,  p.  412. 

^Scientific  Amer.  Supplement,  1893,  p.   14773- 


Enginee:ring  chemistry  491 

English  Patent,  July  2,  1907,  for  polishing  soap,  gives  the  com- 
position as  follows :  "Soap-ash,"  the  waste  calcium  carbonate 
produced  in  the  making  of  ''lyes,"  is  mixed  with  soap,  saltpetre 
and  ammonia.  When  the  polishing  soap  is  required  for  rough 
surfaces,  powdered  silicious  material  is  added.  The  proportions 
are:  "Soap-ash,"  60  parts;  yellow  soap,  30  parts;  saltpetre,  5 
parts;  ammonia,  5  parts. 

"Mineral  soap"  is  the  name  given  to  a  peculiar  kind  of  clay 
found  in  various  parts  of  Wyoming,  U.  S.  The  clay  when  taken 
from  the  quarry  has  a  greenish-yellow  color,  which,  on  exposure 
to  the  air,  soon  changes  to  a  light  cream.  It  forms  an  emulsion 
with  water,  but  only  a  small  portion  dissolves.  Thin  seams  of 
gypsum  and  mirabilite  (a  hydrated  sodium  sulphate),  are  found 
associated  with  the  clay.  An  average  analysis  shows :  SiOs, 
59.78  per  cent.;  AI2O3,  15.10  per  cent;  Fe^Og,  2.40  per  cent.; 
MgO,  4.14  per  cent.;  CaO,  0.73  per  cent.;  H^O,  16.26  per  cent. 

Specifications  for  Sodas  and  Potashes  (1908). 

I.  Caustic  Soda  (Lump  Powdered). — Must  be  a  good  commercial 
grade,  and  contain  not  less  than  94  per  cent,  of  caustic  soda  (NaOH), 
equivalent  to  72.8  per  cent,  alkali  (Na20). 

2.  Granular  Sodium  Carbonate. — Must  be  a  good  commercial  grade 
of  granular  monohydrated  sodium  carbonate,  equal  in  quality  to  "Crystal 
Carbonate,"  and  contain  not  less  than  80  per  cent,  of  anhydrous  sodium 
carbonate   (Na2C0?.),  equivalent  to  46.8  per  cent,  of  alkali   (NaaO). 

Note. — Commercial  sal  soda  (crystallized  carbonate  of  soda)  contains 
approximately  63  per  cent,  of  water  against  18  per  cent,  of  water  in  the 
article  called  for  bj^  the  above  specification.  It  is  also  much  more  soluble 
in  water,  and  in  tropical  countries  is  apt  to  melt  in  its  own  water  of 
crystallization.  The  article  called  for  is  practically  the  so-called  "Crystal 
Carbonate"  of  commerce. 

3.  Crude  Potash. — Must  be  of  the  grade  commercially  known  as 
"Firsts."  The  alkalinity  of  the  sample  due  to  potassium  hydrate  and 
carbonate  combined  must  not  be  less  than  65  per  cent,  when  calculated  as 
potassium  hydrate  (KOH)  equivalent  to  54.57  per  cent,  of  potash  (K2O). 
Must  not  contain  more  than  a  total  of  6  per  cent,  of  soda  salts  when  cal- 
culated as  caustic  soda  (NaOH).     It  always  comes  in  lump  form. 

4.  Caustic  Potash. — Alust  be  of  good  commercial  grade,  and  contain 
not  less  than  75  per  cent,  of  caustic  potash  (KOH),  equivalent  to  62.96 
per  cent,  of  potash  (K2O). 


492  ENGINEERING   CHEMISTRY 

5.  Carbonate  of  Potash  (Granular). — Must  be  of  good  commercial 
grade,  and  contain  not  less  than  75  per  cent,  of  potassium  carbonate 
(K2CO3),  equivalent  to  51.12  per  cent,  of  potash  (K2O). 

Note. — Caustic  soda,  carbonate  of  soda,  crude  potash,  caustic  potash, 
and  carbonate  of  potash  absorb  moisture  from  the  air  with  great  rapidity, 
frequently  becoming  liquefied  thereby.  They  should  be  called  for  in 
small  packages  and  kept  tightly  closed,  except  where  large  quantities  are 
to  be  used  at  once. 

Specifications  for  Glycerine   (1908). 

Must  be  chemically  pure  and  colorless;  must  have  a  specific  gravity 
between  29.7°  and  30°  Baume  (1.253-1.257)  at  60°  F.,  and  must  be  free 
from  fatty  acids,  metallic  impurities,  or  any  adulterations. 

Note. — Gbxerine  is  most  frequently  adulterated  with  water,  which 
lowers  its  specific  gravity.  It  may  also  contain  chlorine,  poisonous  metals 
lime,  traces  of  sulphuric  acid,  etc.  Solutions  of  cane  sugar,  glucose,  dex- 
trin, and  magnesium  sulphate  are  also  used  as  adulterants.  These  would 
not  be  shown  by  the  specific  gravity  test. 

Specifications  for  Concentrated  Lye  (1908). 

Must  be  in  the  form  of  a  powder,  and  put  up  (as  found  commercially) 
in  cans  containing  i  pound  each,  net.  It  must  be  of  the  best  commercial 
grade,  and  must  contain  not  less  than  90  per  cent,  of  anhydrous  caustic 
soda  (NaOH)  equivalent  to  at  least  69.77  per  cent,  of  alkali  (Na20)  with 
about  3  per  cent,  of  carbonate  of  soda  (Na2C03)  and  about  3  per  cent, 
of  chloride  of  sodium   (NaCl). 

Each  can  must  be  marked  with  the  name  of  the  material,  the  trade- 
mark, if  any,  and  the  name  of  the  manufacturer. 

Specifications  for  Resin  (1908). 

1.  For  all  ordinary  purposes  resin  shall  consist  of  equal  proportions 
of  grades  C,  D,  and  E,  known  as  "good  strained  resin,"  C  being  the 
poorest  qualit}^  E  the  best  of  the  three. 

2.  Resin  shall  be  graded  by  sample,  a  piece  being  cut  from  the  top 
head  of  each  barrel,  %-inch  cube,  as  nearly  as  can  be  done.  Uniformity 
of  size  is  important,  as  the  thickness  of  the  piece  determines  the  shade  of 
color,  and,  thus,  its  value. 

3.  These  cubes  or  samples  are  to  be  furnished  by  the  seller  free  of 
charge,  and  will  be  referred  to  in  deciding  its  grade.  For  special  pur- 
poses, if  required,  the  better  grades  are  designated  by  the  letters  F,  G,  H, 
I,  K,  M,  N,  WG,  and  WW ;  WW  being  the  highest  grade. 

4.  The  resin  should  be  perfectly  transparent.  Its  specific  gravity 
should  be  between  1.04  and  1.15.  Its  melting  point  should  not  be  higher 
than  135°  C. ;  it  should  dissolve  easily  in  either  alcohol  or  turpentine.     A 


e;ngine:e:ring  chemistry  493 

definite  cause  for  rejection  will  be  the  presence  of  an  appreciable  amount 
of  dirt  or  pitch. 

5.  Cubes  of  suitable  sizes  of  the  resin  offered  under  a  bid  shall  be 
supplied  by  the  contractor  for  chemical  analysis ;  and  if  this  analysis 
shows  that  adulterants  of  any  nature  have  been  incorporated  in  the  resin, 
it  will  be  cause  for  its  rejection. 

6.  Requisitions  should  specify  the  grade,  using  the  letter  designation 
for  description  of  quality. 

Specifications  for  Cleaning  and  Polishing  Paste  (1908). 

Cleaning  Paste. — Must  be  made  of  a  mixture  of  fine  hard  grits  com- 
bined with  infusorial  earths,  pure  unguents,  oils,  and  coloring  matter,  and 
must  be  practically  free  from  acid,  alkali,  volatile  oils,  water,  or  similar 
substances ;  must  remain  plastic  at  32°  F. ;  must  not  liquefy  so  as  to  run 
at  120°  F.,  and  when  thoroughly  heated  to  a  temperature  of  212°  F.  for 
I  hour  it  must  not  lose  more  than  one-half  of  i  per  cent,  in  weight.  It 
will  be  considered  free  from  acid  if,  when  applied  to  polished  brass,  it 
shows  no  action  or  green  coloration  at  the  end  of  24  hours. 

Polishing  Paste. — The  basis  of  the  polishing  paste  must  be  natural 
oxide  of  iron  combined  with  proper  oils.  It  must  be  free  from  alkali  and 
cyanide  of  potassium,  and  when  applied  to  polished  brass  it  must  produce 
no  corrosion  or  green  coloration  at  the  end  of  24  hours.  It  must  equal 
in  grit,  polishing  power,  and  other  respects  the  standard  sample  to  be 
seen  at  the  general  storekeepers'  offices  of  the  various  navy  yards. 

References. 

"American  Soaps,"  by  Henry  Gathman,  Chicago,  1894. 

"Soaps,"  by  George  H.  Hurst.    A  practical  manual  of  the  manufacture  of 

domestic,  toilet  and  other  soaps.     London,  1898. 
"The  Art  of  Soap  Making,"  by  Alex.  Watt,  London,  1896. 
"Analysis  of  Washing  Powders,"  Amer.  Chem.  Jour.,  14,  623. 


494  ENGINEERING   CHEMISTRY 

THE  ANALYSIS  OF  PARIS  GREEN. 

When  pure,  the  composition  of  Paris  green  may  be  stated  as 
an  aceto-arsenite  of  copper — a  combination  of  arsenious  acid, 
oxide  of  copper  and  acetic  acid;  having  CuO,  31.29  per  cent.; 
AS2O3,  58.65  per  cent. ;  and  acetic  acid  10.06  per  cent. 

This  formula  is  empirical,  since  a  portion  of  the  arsenic  may 
exist  as  arsenic  acid  as  well  as  arsenious  acid  and  copper  sub- 
oxide may  be  present  in  small  amounts  with  the  copper  oxide. 

The  chemical  examination  of  pure  Paris  green  is  comparatively 
simple,  since  it  is  soluble  in  slight  excess  of  ammonia  forming  a 
dark  blue  solution.  If  it  be  desired  to  determine  the  amount  of 
AS2O3,  a  rapid  and  accurate  method  is  by.  the  use  of  a  standard 
solution  of  potassium  bichromate,  whereby  arsenious  acid,  in  acid 
solution,  is  oxidized  to  arsenic  acid  by  the  bichromate.  The  bi- 
chromate solution  should  be  of  such  strength  that  i  cc.  of  it  cor- 
responds to  0.00495  gram  As^Og.  Full  instructions  for  this 
method  will  be  found  in  Sutton's  "Volumetric  Analysis,"  p.  138. 
If  arsenic  acid  is  present  in  the  Paris  green,  its  amount  can  be 
determined  as  follows :  Dissolve  a  sample  of  the  green  in  dilute 
hydrochloric  acid,  pass  H,2S  gas  through  the  solution  until  sat- 
urated, keeping  the  temperature  of  the  liquid  at  about  70°  C. 
Filter,  wash  the  sulphide  of  arsenic  thoroughly  with  water  con- 
taining 11,28,  transfer  precipitate  and  filter  to  a  flask;  add  excess 
of  saturated  solution  of  mercuric  chloride  in  HCl  (specific  grav- 
ity i.12)  and  warm  until  a  white  precipitate  forms,  water  being 
added  until  the  volume  of  HCl  in  the  liquid  amounts  to  about  one- 
sixth.  Add  excess  of  standard  bichromate  solution  from  a  burette 
and  determine  excess  over  that  required  to  oxidize  the  arsenious 
acid,  by  means  of  a  standard  solution  of  ferrous  sulphate.  By 
this  operation  the  total  arsenic  in  the  Paris  green  is  determined — 
as  AsigOg.  If  now  the  amount  already  existing  as  AsgOs  be  found 
and  subtracted  from  the  total  AS2O3,  the  difference  should  be 
calculated  to  As^sOg — which  would  be  the  amount  of  arsenic  acid 
desired. 

Reference. 

"The  Estimation  of  Arsenic  in  Paris   Green,"  by  Thorn   Smith,  /,  Am. 
Chem.  Soc,  21,  769. 


ENGINEERING    CHEMISTRY 


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496  ENGINEERING   CHEMISTRY 

PAINT  ANALYSIS. 

Paint  is  a  liquid  preparation  having  a  two-fold  use.  Primarily 
it  acts  as  a  protecting  coating  against  the  action  of  the  weather, 
and  simultaneously  as  a  decorative  agent. 

The  liquid  is  usually  linseed  oil  and  turpentine  and  the  color- 
ing-matter or  body  some  solid  pigment,  such  as  finely  ground  red 
oxide  of  iron. 

It  is  essential  in  the  production  of  a  good  paint  that  the  oil 
used  should  be  one  that,  upon  drying  on  the  surface  applied, 
should  become  hard,  lustrous,  and  somewhat  elastic. 

Unseed  oil  excels  all  others  in  use  for  this  purpose,  sophisti- 
cation thereto  only  deteriorates  the  quality. 

Four  qualities  are  essential  in  paint:  i.  Durability;  2.  Work- 
ing qualities ;  3.  Drying  properties ;  4.  Covering  power. 

The  following  list  of  pigments,  with  their  chemical  composition 
stated,  will  give  an  idea  of  the  great  variety  that  can  be  used  in 
paints  for  outside  work :  The  list  would  be  largely  increased 
were  other  pigments  included  that  are  used  for  interior  decorative 
work  only. 

Red  Pigments. — Indian  red,  Tuscan  red  (Fe^Og),  vermillion 
(HgS),  red  lead  (Pb304),  antimony  vermilion  (Sb^Ss).  Iron 
oxide,  Indian  red,  and  Tuscan  red  can  be  analyzed  by  the  scheme 
for  hematite. 

Brown  Pigments. — Umbers  (Fe^Og,  MnOg,  etc.).  Van  Dyke 
brown  (Fe^Og,  carbon),  manganese  brown  (Mng04)  and  sepia. 
The  composition  of  sepia  is  as  follows : 

Per  cent. 

Melanin    78.00 

CaCOs     10.40 

MgCOa   7.00 

Alkaline  sulphates    2.16 

Organic    mucus   1.84 

99.40 

White  Pigments.— White  lead  (2PbC03.PbHoOo),  lead  sul- 
phate (PbS04),  zinc  white  (ZnO),  sulphide  of  zinc,  white 
(ZnS),  "lithopone."     Also  the   following,   added  oftentimes  as 


I 


ENGINEERING    CHEMISTRY  497 

fillers:  barytes  (BaS04),  hlanc  fixe  (artificial  barytes), 
gypsum  (CaS04),  strontium  white  (SrS04),  whiting  (CaCOg), 
china-clay  (kaolin),  and  magnesite  (MgCOg). 

Yellow  and  Orange  Pigments. — Chrome  yellow  (2PbCr04), 
Chinese  yellow  (PbO.PbCr04),  zinc  chrome  ZnCr04),  realgar 
(As.Sg),  "cadmium  yellow"  (CdS),  "King's  yellow"  (As.S.,), 
yellow  ochre  {Vtfi^,  Al^Og,  SiOs  etc.),  and  Siennas  (FcoOg, 
H,0,Mn304). 

Green  Pigments. — Chrome  green,  (CrgO),  copper  green 
(CuA),  mineral  green  (malachite),  cobalt  green  (ZnO,  CoO, 
P2O5,  etc.),  manganese  green  (BaO,Mn02,  etc.),  emerald  green 
("Paris  green,"  3CuOAs203.Cu(C2H302)2),  and  Brunswick 
green  (compounded  of  barytes,  chrome  yellow,  Prussian  blue,  etc., 
also  called  chrome  green  when  lead  sulphate  is  used  instead  of 
barytes ) . 

Black  Pigments. — Lampblack  (carbon),  bone-black  (carbon 
and  Ca3HP04),  vegetable  black,  Frankfort  black,  coal-tar  black, 
asphaltum  black,  and  graphite  black  (C). 

Blue  Pigments. — Ultramarine  (Si02,Al203>Na20,S),  Prussian 
blue,  Chinese  blue,  or  Brunswick  blue  (FcgCigNig),  cobalt  blue  or 
smalts  (AI2O3,  CoO),  Bremen  blue  (CuHoOa),  and  copper  blue 
(CuO,C02H20). 

The  various  colored  lakes,  carmines,  analine  lakes,  etc.,  have 
but  a  limited  application  in  engineering  chemistry.  Their  methods 
of  manufacture  and  assay  can  be  advantageously  studied  by  ref- 
erence to  "Painters'  Colors,  Oils  and  Varnishes,"  by  George  H. 
Hurst,  F.  C.  S.,  London,  1892,  pp.  249-282. 

The  analysis  of  white  lead  pure,  not  ground  in  oil  (2PbC03). 
Pb.HoOs),  can  be  performed  as  follows: 

Take  i  gram  of  the  white  lead,  transfer  to  a  No.  3  beaker,  add 
25  cc.  dilute  nitric  acid  and  warm  gently  until  solution  is  com- 
plete. Dilute  sulphuric  acid  is  added  in  slight  excess  and  10  cc. 
of  alcohol.  Allow  to  stand  20  minutes,  filter  off  the  lead  sul- 
phate, wash  well  with  water,  dry,  ignite,  and  weigh  as  PbS04. 
The  weight  of  PbS04,  multiplied  by  0.85258,  will  give  the  weight 
of  (2PbC03).(PbH20,2). 
32 


498  ENGINEERING   CHEMISTRY 

If  the  white  lead  is  ground  in  oil  ("Paste  White  Lead"  con- 
taining about  8  per  cent,  of  oil),  it  will  be  necessary  to  extract 
the  oil  before  the  above  determinations  of  lead  can  be  made. 
The  usual  solvent  is  petroleum  ether,  Thompson^  prefers  benzol 
C.  P.  Twenty  grams  of  the  paint  are  treated  with  sufficient  pe- 
troleum ether,  in  a  Soxhlet  apparatus,  and  the  oil  extracted.  By 
evaporation  of  the  petroleum  ether  in  a  weighed  beaker  the 
amount  of  oil  is  determined. 

Hurst-  treats  the  lead  paint  with  strong  nitric  acid,  whereby  the 
oil  is  decomposed  "into  an  insoluble  greasy  matter;"  this  does  not 
interfere  with  the  determination  of  the  lead  as  sulphate.  If, 
however,  the  oil  is  to  be  determined  also,  then  he  recommends  the 
use  of  petroleum  ether.  After  the  extraction  of  the  oil,  either  by 
benzol  or  petroleum  ether,  the  residue  is  dried  at  102°  C,  and 
weighed  portions  taken  therefrom  for  the  determination  of  the 
lead,  as  sulphate. 

Instead  of  determining  the  lead  as  sulphate,  many  chemists 
prefer  to  dissolve  the  dried  lead  paint  in  acetic  acid  to  a  clear 
solution,  and  precipitate  the  lead  with  bichromate  of  potash  as 
lead  chromate.  This  latter  is  weighed  as  PbCrO^  in  a  gooch 
crucible  and  the  weight  found  calculated  to  (2PbC03). 
(PbH,0,). 

Thompson  recommends  the  absorption  method  for  carbon  di- 
oxide determination. 

The  water  of  hydration,  in  the  dried  paint,  is  found  by  calcu- 
lating the  amount  of  lead  sulphate  or  lead  chromate  into  lead  ox- 
ide and  subtracting  this  amount  of  lead  oxide,  plus  the  amount  of 
carbon  dioxide  found  from  100.  The  difference  is  the  water  of 
hydration.  The  water  of  hydration  cannot  be  determined  accu- 
rately in  paint  from  which  the  oil  has  been  extracted  since  a 
small  amount  of  organic  matter  remains  which  vitiates  the  result. 

The  hygroscopic  water  is  determined  by  drying  a  sample  of  the 
paint  at  98°  C.  to  constant  weight.  The  loss  represents  moisture, 
provided  no  volatile  oil  is  present. 

1  J.  Soc.  Chem.  Ind.,  15,  432. 

-  "Painters'  Colors,  Oils  and  Varnishes,"  p.  44. 


ENGINEERING   CHEMISTRY  499 

Analysis  of  White  Lead  Paints.^ 

(Dry,  not  ground  in  oil.) 
123456 

PbO    86.35      85.93      83.77      84.42      86.5        86.24 

CO2  10.44       11.89       15.06       14.45       11.3         11.68 

H2O    2.95        2.01         i.oi         1.36        2.2  1.61 

Total    99.74      99.83      99.84     100.23     loo.o        99.53 

from  which  the  composition  of  the  white  leads  can  be  calculated 
to  be: 

123456 

PbCOa   63.35      72.15      91.21      87.42     68.36      70.87 

PbHiOa   36.14      27.68        8.21       12.33      31.64      28.66 

Moisture    0.25         —  0.42        0.48  —  — 

Total    99.74      99.83      99.84     100.23     100.00      99.53 

No.  I.     English  make.    Made  by  Dutch  process;  of  very  good 

qualit}^ 
No.  2.     English  make.    Made  by  Dutch  process ;  of  very  good 

quality. 
No.  3.     Kerms    white.      Made    by    precipitation    with    carbon 

dioxide.     It  is  deficient  in  body,  although  of  good 

color. 
No.  4.     German  make.     Precipitated  by  carbon  dioxide;    of 

good  color,  but  deficient  in  body. 
No.  5.     German  make.   Made  by  Dutch  process ;  a  good  white. 
No.  6.     German   make.     Made   by  precipitation   with   carbon 

dioxide ;  quality  fair. 


ANALYSIS  OF  WHITE  PIGMENTS.^ 
Method  for  Very  Small  Amounts  of  Iron. 
Lead  Pigments. — Treat  sample  with  HNO3  (i  •  i)  in  usual 
manner,  dilute  with  H^sO,  add  H0SO4  to  precipitate  bulk  of  lead 
(not  necessary  to  evaporate  down)  ;  cool,  filter,  wash  w^th  i  to  2 
per  cent,  of  H,2S04,  make  filtrate  just  alkaline  with  NH4OH,  then 
just  acid  with  dilute  HNO3,  determine  iron  calorimetrically  by  the 
thiocynate  method,  using  same  amounts  of  reagents  in  preparing 
standards.     If  sample  contains  insoluble  matter,   filter  out  and 

^  "Painters'  Colors,  Oils  and  Varnishes,"  by  G.   H.  Hurst,  F.  C.  S.,  p.  39. 
^Proceedings,  Am.  Soc.  Test.  Mats.,  Vol.  XIV  (1914). 


500  ENGINEERING   CHEMISTRY 

wash  with  hot  water  till  Pb-free,  and  to  filtrate  add  HoSO^  and 
proceed  as  given.  The  insoluble  is  ignited,  treated  with  HF  and 
HoSO^  in  usual  manner,  brought  into  solution  (filter  out  any 
BaS04),  and  added  to  filtrate  from  PbS04.  If  necessary,  solu- 
tion may  be  made  up  to  volume  'and  aliquots  taken. 

Other  Pigments. — Treat  as  above,  omitting  the  addition  of 
H.SO^. 

General  Method. 

Co/or.— -Compare  with  sample  selected  as  a  standard.  "Vol- 
ume" or  "apparent  gravity"  to  be  determined  by  the  Scott  vol- 
umeter. True  specific  gravity  to  be  determined  by  means  of  a 
pyknometer,  using  C.  P.  benzole  or  by  Thompson's  method.^ 

Fineness  Test. — Determine  with  No.  21  silk  bolting  cloth  or  a 
300-mesh  bronze  wire  screen.  The  Thompson  classifier^  may 
also  be  used,  supplemented  by  a  microscopic  study. 

A  qualitative  analysis  of  all  pigments  should  first  be  made. 

Basic  Carbonate  of  Lead. 

Basic  cabonate  of  lead  (white  lead)  should  approach  the  com- 
position 2PbC03.Pb(OH)^. 

Moisture. — Moisture  may  be  determined  by  heating  2  grams  for 
2  hours  in  a  steam- jacketed  oven  at  atmospheric  pressure. 

Total  Lead. — If  pure  product  is  being  examined,  dissolve  i 
gram  in  20  cc.  of  nitric  acid  ( i :  i )  in  a  covered  beaker,  heating 
till  all  CO2  is  expelled ;  wash  off  cover,  dilute  to  about  120  cc.  with 
hot  w^ater  and  heat  till  all  basic  salt  is  in  solution.  Filter  off  any 
insoluble,  wash  with  hot  water  till  Pb-free,  ignite  and  weigh 
"insoluble  matter."  (Insoluble,  if  appreciable,  should  be  ex- 
amined for  BaS04,  SiO^,  and  silicates.)  To  filtrate  add  20  cc.  of 
H2SO4  (1:1)  and  evaporate  to  fumes  of  SO3,  cool,  add  about 
150  cc.  of  water  and  150  cc.  of  ethyl  alcohol;  allow  to  stand  cold 
2  hours,  filter  on  a  gooch  crucible,  wash  with  95  per  cent,  ethyl 
alcohol,  dry  i  hour  at  110°  C,  and  weigh  PbS04;  calculate  to 
PbO  or  to  basic  carbonate.  Instead  of  determining  the  lead  as 
sulphate  the  nitric  acid  solution  may  be  made  slightly  alkaline  with 

'^Proceedings,  Am.   Soc.  Test.  Mats.,  Vol.  XIII,  p.  407   (1913). 
^Proceedings,  Am.  Soc.  Test.  Mats.,  Vol.  X,  p.  601    (1910). 


ENGINEERING   CHEMISTRY  5OI 

NH4OH  or  NaOH,  then  acid  with  acetic  acid,  and  to  to  15  cc. 
of  a  10  per  cent,  solution  of  potassium  dichromate  added;  heat 
till  the  yellow  precipitate  assumes  an  orange  color,  Let  settle  and 
filter  on  a  gooch  crucible,  washing  by  decantation  with  hot  water 
till  the  washings  are  colorless,  finally  transferring  all  of  the  pre- 
cipitate. Finally  wash  with  95  per  cent,  ethyl  alcohol  and  then 
ether  dry  at  110°  C.  for  i  hour  and  weigh  PbCr04. 

Complete  Analysis. — This  method  with  a  pure  white  lead  gives 
good  results  for  CO2  and  H2O,  but  the  residue  is  only  an  ap- 
proximation of  the  true  PbO.  In  the  absence  of  acetic  acid  or 
other  organic  matter,  for  example,  unextracted  vehicle,  heat  i 
gram  in  a  porcelain  boat  in  a  current  of  dry  CO,2  free  air,  ab- 
sorbing the  water  in  H,2S04  and  CaClg  and  the  CO2  in  soda  lime 
or  KOH  solution  (specific  gravit)^  1-27).  By  weighing  the  residue 
of  PbO  in  the  boat  all  the  factors  for  determining  the  total  com- 
position are  obtained.  Calculate  the  CO2  to  PbCOg  and  the  H2O 
to  Pb(OH)2;  excess  H2O  is  due  to  moisture. 

Acetic  Acid. — Thompson's  method^  is  as  follows :  Eighteen 
grams  of  the  dry  white  lead  are  placed  in  a  500-cc.  flask,  this  flask 
being  arranged  for  connection  with  a  steam  supply,  and  also 
with  an  ordinary  Liebig  condenser.  To  this  white  lead  is  added, 
40  cc.  of  sirupy  phosphoric  acid,  18  grams  of  zinc  dust,  and  about 
50  cc.  of  water.  The  flask  containing  the  material  is  heated 
directly  and  distilled  down  to  a  small  bulk.  Then  the  steam  is 
passed  into  the  flask  until  it  becomes  about  half  full  of  condensed 
water,  when  the  steam  is  shut  off  and  the  original  flask  heated 
directly  and  distilled  down  to  the  same  bulk — this  operation  being 
conducted  twice.  To  the  distillate  which  is  received  in  a  larger 
flask  is  added  i  cc.  of  sirupy  phosphoric  acid  to  insure  a  slightly 
acid  condition.  The  flask  is  then  heated  and  distilled  using  a 
spray  trap,  to  a  small  bulk  say,  20  cc.  Steam  is  then  passed 
through  the  flask  until  it  contains  about  200  cc.  of  condensed 
water,  when  the  steam  is  shut  off  and  the  flask  heated  directly. 
These  operations  of  direct  distillation  and  steam  distillation  are 
conducted  until  10  cc.  of  the  distillate  require  but  a  drop  of  N/io 
alkali  to  produce  a  change  in  the  presence  of  phenolphthalein. 

1  J.  Soc.  Chem.  Ind.,  Vol.  24,  p.  487  (1905). 


502  e:nginee:ring  chemistry 

Then  the  bulk  of  the  distillate  is  titrated  with  N/io  sodium  hy- 
droxide, and  the  acetic  acid  calculated.  It  will  be  found  very 
convenient  in  this  titration,  which  amounts  in  some  cases  to  600 
to  700  cc,  to  titrate  the  distillate  when  it  reaches  200  cc,  and  so 
continue  titrating  every  20  cc.  as  it  distills  over. 

If  the  white  lead  contains  appreciable  amounts  of  chlorine  it  is 
well  to  add  some  silver  phosphate  to  the  second  distillation  flask 
and  not  carry  the  distillation  from  this  flask  too  far  at  any  time. 

Carbon  Dioxide. — Determined  by  evolution  with  hydrochloric 
acid,  weighing  in  soda  lime,  KOH  solution  or  by  absorbing  in 
Ba(OH)2  solution  and  titrating  or  weighing  the  BaCOg.^ 

Total  Sulphuric  Anhydride  (in  absence  of  BaS04)  : — Deter- 
mined by  dissolving  in  HCl  and  NH4CI,  precipitating  with  NagCOg 
solution  in  excess,  filtering,  acidifying  filtrate  with  HCl  and  pre- 
cipitating as  BaS04. 

(In  presence  of  BaS04).  Determined  as  under  basic  sulphate 
of  lead  containing  BaS04. 

Sidphur  Dioxide. — Weigh  2  grams  into  a  250  cc.  beaker,  add 
100  cc.  of  distilled  water  that  has  been  freshly  boiled  and  cooled, 
then  5  cc.  of  concentrated  HCl;  stir  thoroughly,  let  stand  15 
minutes,  and  titrate  with  o.oi  normal  iodine  solution,  using  starch 
as  indicator.  Blank  should  be  run  on  reagents  and  correction 
made. 

Metallic  Lead. — Weigh  50  grams  of  the  sample  into  a  400  cc. 
beaker,  add  a  little  water  and  add  slowly  60  cc.  of  40  per  cent, 
acetic  acid  and  after  effervescence  has  ceased  boil  on  hot  plate. 
Fill  the  beaker  with  water,  allow  to  settle,  and  decant  clear  solu- 
tion. Add  100  cc.  of  a  mixture  of  360  cc.  of  strong  NH4OH, 
1,080  cc.  of  water,  2,160  cc.  of  80  per  cent,  acetic  acid  and  boil 
until  all  solution  is  complete.  Fill  beaker  with  water  allow  to 
settle  and  decant  clear  solution.  Collect  residue  on  watch  crystal, 
floating  off  everything  but  metallic  lead.  Dry  and  weigh.  Re- 
sult X  2  =  percentage  of  metallic  lead  in  sample. 

Note. — If  soluble  barium  compounds,  as  for  example,  BaCOg, 

1  See  J.  M.  Camp's  method  for  carbon  in  steel  in  Phillips,  "  Methods  of  Analysis  in 
Pittsburgh  District;  "  Dudley  &  Voorhees'  method  in  Scott,  "  White  Paints  and  Painting 
Materials,"  p.  84;  and  an  article  by  Wysor,  in  Chemical  Etigineer,  Vol.  11,  p.  26. 


^NGINDEIRING   CHEMISTRY  503 

are  present,  the  lead  and  barium  are  separated  together  as  sul- 
phates, the  precipitate  of  BaSO^  +  PbSO^  treated  with  hot  acid 
ammonium  acetate  solution,  and  the  lead  determined  in  the  solu- 
tion by  the  sulphate  or  chromate  method.  The  BaSO^  is  weighed 
as  such.  If  sample  contains  much  calcium  or  magnesium,  deter- 
mine lead  by  chromate  method,  or  separate  the  lead  by  a  hydrogen- 
sulphide  precipitation,  dissolve  PbS  in  hot  dilute  HNO3  and  deter- 
mine lead  as  PbSO^  or  PbCrO^.  Iron,  aluminum,  zinc,  calcium 
and  magnesium  may  be  determined  in  filtrate  from  PbS  by  usual 
methods. 

Basic  Sui^phate;  op  I^ead. 

Moisture. — Heat  2  grams  of  the  sample  2  hours  in  an  air  bath 
at  105°  C. 

Insoluble  Matter. — Treat  i  gram  of  sample  in  a  600  cc.  beaker 
with  20  cc.  of  water,  20  cc.  of  concentrated  HCl  and  10  grams  of 
NH4CI ;  cover  and  heat  about  10  minutes,  then  add  about  400  cc. 
of  water  and  boil  10  minutes.  Filter  and  wash  thoroughly  with 
hot  water.  Ignite  and  weigh  insoluble  matter.  If  sample  con- 
tains soluble  silica,  treat  with  HCl  and  HgO  and  evaporate  to 
dryness,  then  as  above  with  HgO,  HCl  and  NH4CI,  finally  diluting 
and  boiling. 

Total  Soluble  Sulphates  {in  the  Absence  of  BaSO^). — Treat  0.5 
gram  of  the  sample  with  5  cc.  of  water,  3  grams  of  NH4CI  and 
5  cc.  of  HCl  saturated  with  bromine;  digest  (covered)  on  steam 
bath  about  15  minutes,  add  25  cc.  of  H2O,  neutralize  with  dry 
NaaCOg  and  add  about  2  grams  more,  boil  10  to  15  minutes;  let 
settle,  dilute  with  hot  water,  filter  and  wash  with  hot  water ;  redis- 
solve  in  HCl,  reprecipitate  as  above  and  wash  thoroughly  with 
hot  water.  Acidify  united  filtrates  with  HCl,  adding  a  slight 
excess ;  boil  and  add  slight  excess  of  10  per  cent.  BaCl^  solution. 
Let  stand  on  steam  bath  for  i  hour,  filter,  wash  with  hot  water, 
ignite  and  weigh  BaS04.  Calculate  to  SO3  (includes  SO3  formed 
from  SO2). 

Total  Soluble  Sulphate  (in  the  Presence  of  BaSO^). — Treat  i 
gram  in  a  600  cc.  beaker  with  10  cc.  of  H2O,  10  cc.  of  strong 
HCl,  saturated  with  bromine,  and  5  grams  of  NH4CI  heat  on  a 


504  ENGINEERING    CHEMISTRY 

steam  bath  in  a  covered  beaker  for  5  minutes,  add  hot  water  to 
make  about  400  cc,  boil  for  5  minutes,  and  filter  to  separate  any 
insoluble  material.  (A  pure  pigment  should  be  completely  dis- 
solved.) Wash  with  hot  water,  ignite  and  weigh  the  insoluble. 
Remove  lead  with  NagCOs  as  above,  making  a  double  precipita- 
tion, acidify,  and  to  the  boiling  hot  filtrate  add  slowly,  with  stir- 
ring, 20  cc.  of  a  10  per  cent.  BaCU  solution;  let  stand  for  2  hours 
on  the  steam  bath,  filter,  wash,  ignite,  and  weigh  as  BaSO^  (in- 
cludes SO3  formed  from  SO2).  If  sample  contains  much  calcium 
this  precipitate,  after  ignition,  should  be  treated  as  under 
''gypsum." 

Soluble  Zinc  Sulphate. — Boil  2  grams  of  the  sample  with  150 
cc.  of  water  and  50  cc.  of  alcohol  for  30  minutes,  filter,  and  wash 
with  a  mixture  of  alcohol  and  water  (i  :  3).  Heat  filtrate  to 
boiling-  and  expel  most  of  the  alcohol ;  then  determine  SO3  by 
usual  method  of  precipitation  with  BaCls-  Calculate  to  ZnSO^ 
and  so  SO3. 

Total  Lead  and  Zinc  {in  the  Absence  of  Calcium  and  Mag- 
nesium).— Insoluble  matter  and  soluble  810,2,  if  present,  should 
be  removed  before  adding  H2SO4.  Dissolve  i  gram  by  boiling 
15  minutes  with  250  cc.  of  water  and  20  cc.  of  concentrated 
HNO3,  add  5  cc.  of  concentrated  H2SO4,  and  evaporate  to  copious 
fumes  of  SO3 ;  cool,  add  250  cc.  of  water,  let  stand  cold  2  hours, 
filter  on  gooch  crucible,  wash  with  i  per  cent.  H0SO4,  ignite  and 
weigh  as  PbS04. 

Iron  and  aluminum,  if  present,  should  be  removed  before  pre- 
cipitating zinc.  If  Ca  and  Mg  are  also  present,  see  method  below. 
To  determine  small  amounts  of  Fe,  Al  and  Mn  (in  absence  of  Ca 
or  Mg),  a  large  portion  of  sample  should  be  treated  as  above, 
the  Pb  removed  as  PbS04,  Fe  and  Al  precipitated  with  NH4OH 
(redissolving  and  reprecipitating)  ;  ignite  and  weigh  Al^Og  -f- 
Feo03.  This  precipitate  may  be  fused  with  KHSO4  and  Fe  de- 
termined volumetrically,  if  desired.  In  filtrate  from  Al  and  Fe, 
Mn,  if  present,  may  be  determined  by  precipitating  with  NH4OH 
and  bromine,  finally  weighing  as  Mn304.  Make  filtrate  up  to 
volume  and  determine  Zn  in  an  aliquot  as  ZuoPgO;,  as  ZnO  or 
volumetrically  with  K4Fe(CN)6. 


ENGINEERING    CHEMISTRY  505 

Evaporate  the  filtrate  to  about  lOO  cc,  cool,  add  5  grams  of 
microcosmic  salt  dissolved  in  water,  then  add  NH4OH  until  the 
solution  is  just  neutral  to  litmus  paper.  Add  2  drops  of  NH4OH 
and  I  cc.  of  acetic  acid,  stir  vigorously,  heat  on  steam  bath  for  i 
hour  (the  precipitate  should  assume  a  crystalline  character  and 
settle  well).  Filter  on  a  gooch  crucible,  wash  with  hot  water, 
ignite  at  first  at  a  low  temperature  and  finally  to  redness,  cool,  and 
weigh  as  zinc  pyrophosphate.     Calculate  to  ZnO. 

Total  Lead  and  Zinc  {in  the  Presence  of  Calcium  and  Mag- 
nesium).— With  a  sample  containing  calcium  or  magnesium  salts 
the  lead  should  be  precipitated  as  sulphide  from  a  slightly  acid 
(HCl)  solution,  the  PbS  dissolved  in  hot  dilute  HNO3  and  the 
lead  determined  as  sulphate.  Filtrates  from  the  PbS  are  boiled 
to  expel  H2S,  a  little  bromine  water  added  to  oxidize  iron  (if 
present),  boil  to  expel  bromine,  and  then  add  NH4OH  in  slight 
excess.  Filter  and  wash  precipitate  of  Fe(OH)3  +  Al(OH)3 
with  hot  water.  (If  appreciable,  redissolve  in  hot  dilute 
HCl  and  reprecipitate  with  NH4OH,  ignite  and  weigh  Fe^Og  + 
AIqOs-)  Manganese,  if  present,  can  be  precipitated  by  adding 
bromine  and  NH4OH  and  warming;  filter,  wash  with  hot  water, 
ignite  and  weigh  as  Mn304.  Unite  all  of  the  filtrates,  make 
slightly  acid  with  acetic  acid,  heat  to  boiling  and  pass  H2S  into 
the  hot  solution  till  saturated  (20  to  30  minutes)  ;  add  5  grams 
of  NH4CI  and  let  stand  5  hours ;  filter,  wash  with  hydrogen  sul- 
phide water,  dissolve  the  ZnS  in  hot  dilute  HCl,  boil  off  the  HgS, 
filter  out  any  separated  sulphur  and  determine  the  zinc  as  ZngP^O^, 
as  described.  Calcium  may  be  determined  in  the  filtrate  from 
the  ZnS  by  expelling  H2S  and  then  adding  NH4OH  and  ammon- 
ium oxalate  in  usual  manner.  Titrate  with  KMnO^.  In  the 
filtrate  from  calcium  determine  magnesium  in  usual  manner  by 
precipitating  with  sodium  phosphate  solution,  finally  weighing  as 
Mg2P207.  When  calcium  and  magnesium  are  present  zinc  is 
best  determined  volumetrically  by  Low's^  ferrocyanide  method. 
In  the  absence  of  iron  and  manganese,  take  the  filtrate  from  the 
PbS,  make  alkaline  with  NH4OH,  then  just  acid  with  HCl;  add 
3  cc.  of  concentrated  HCl,  dilute  to  250  cc,  heat  and  titrate  just 

1  "Technical  MeUiodsof  Ore  Analysis,"  p.  209  (1906). 


506  ENGINEERING    CHEMISTRY 

as  in  standardizing  the  solution.    When  iron  and  manganese  are 
present  for  oxidized  ores  as  described  by  Low. 

Lead  may  also  be  determined  by  boiling  i  gram  of  the  sample  in 
50  cc.  of  water  plus  100  cc.  of  a  mixture  of  125  cc.  of  80  per  cent, 
acetic  acid,  95  cc.  of  strong  NH4OH  and  100  cc.  of  water,  diluting 
to  about  200  cc,  filtering  out  any  insoluble,  washing  with  above 
mixture  and  then  precipitating  with  K^CrgOy,  finally  weighing  as 
PbCr04.  Zinc  may  be  determined  by  boiling  i  gram  of  the 
sample  with  30  cc.  of  water,  4  grams  of  NH4CI  and  6  cc.  of 
concentrated  HCl ;  dilute  to  200  cc.  with  hot  water,  add  2  cc.  of 
saturated  sodium  thiosulphate  solution  and  titrate  in  usual  man- 
ner with  ferrocyanide. 

Sulphur  Dioxide. — Digest  2  grams  of  the  sample  with  frequent 
stirring  in  100  cc.  of  freshly  boiled  cold  water  and  5  cc.  of  con- 
centrated HCl;  let  stand  10  to  15  minutes,  add  an  excess  of  o.oi 
normal  iodine  solution  and  titrate  back  with  o.oi  normal  sodium 
thiosulphate  solution,  using  starch  indicator.  Report  as  SO^. 
Run  blank  on  reagents  and  make  corrections. 

Carbon  Dioxide. — Determined  as  under  basic  carbonate  of  lead, 
noting  precautions  for  sulphides,  etc.,  under  lithopone. 

Calculations. — Report  soluble  SO3  as  ZnS04;  deduct  ZnO 
equivalent  of  the  ZnS04  from  total  ZnO  and  report  residue  as 
ZnO.  Deduct  soluble  SO3  and  SO3  equivalent  to  SOg  from  total 
SO3  calculate  remainder  to  PbS04;  subtract  PbO  equivalent  of 
PbS04  from  total  PbO  and  report  remainder  as  PbO. 

Zinc-Le)ad  and  Leaded  Zincs. 
Zinc-lead  and  leaded  zincs  (Ozlo  white)  are  to  be  analyzed  by 
methods  given  under  "basic  sulphate  of  lead." 

Zinc  White. 
Moisture. — Heat  2  grams  in  air  bath  at  105°  C.  for  2  hours. 

Loss  on  Ignition. — Ignite  i  gram  over  Bunsen  burner  for  15 
minutes.  Soluble  zinc  sulphate,  total  sulphate,  insoluble  matter, 
CO2,  lead,  zinc,  iron,  aluminum,  SOo,  calcium  and  magnesium  are 
to  be  treated  as  under  "basic  sulphate  of  lead." 


ENGINEERING    CHEMISTRY  507 

I^ITHOPONE. 

Lithopone  (Ponolith,  Jersey  Lily  White,  Becton  White,  Charl- 
ton White,  Orr's  White)  should  contain  about  69  to  70  per  cent, 
of  barium  sulphate,  the  remainder  being  zinc  sulphide  with  small 
amounts  of  zinc  oxide  and  carbonate. 

Analysis  of  Pure  Lithopone} 

Moisture. — Heat  2  grams  of  the  sample  for  2  hours  at  105°  C. 
There  should  be  less  than  0.4  per  cent,  of  moisture. 

Insoluble  and  Total  Zinc. — ^Take  i  gram  in  a  200  cc.  beaker,  add 
10  cc.  of  strong  hydrochloric  acid,  mix,  and  add  in  small  portions 
about  I  gram  of  potassium  chlorate;  then  heat  on  the  water  bath 
until  about  half  of  the  liquid  is  evaporated.  Dilute  with  hot 
water,  add  5  cc.  of  dilute  sulphuric  acid  (i  :  10)  ;  boil,  allow  to 
settle,  filter,  wash,  ignite  and  weigh  the  insoluble  which  will  be 
total  barium  as  barium  sulphate  together  with  any  other  insoluble. 
Make  a  qualitative  examination  for  alumina  and  silica  (not  likely 
to  be  present).  Heat  the  filtrate  from  the  insoluble  to  boiling, 
add  sodium  carbonate  solution,  drop  by  drop,  until  all  of  the  zinc 
is  precipitated  as  carbonate,  filter  on  a  gooch  crucible,  wash, 
ignite  and  weigh  as  zinc  oxide. 

Zinc  Sulphide.'^ — Digest  i  gram  with  100  cc.  of  i  per  cent, 
acetic  acid  at  room  temperature  for  ^  hour,  then  filter  and  wash ; 
determine  the  zinc  in  the  filtrate  as  in  the  preceding  analysis.  The 
difference  between  the  total  zinc  oxide  and  the  zinc  oxide  soluble 
in  acetic  acid  multiplied  by  1. 19749  gives  the  zinc  present  as  sul- 
phide. The  zinc  soluble  in  acetic  acid  may  be  reported  as  oxide, 
though  it  may  be  partly  carbonate.  This  method  of  analysis  as- 
sumes the  absence  of  impurities  such  as  salts  of  iron. 

Analysis  of  Lithopone  in  the  Presence  of  Foreign  Substances.^ 

Soluble  Salts. — Wash  2  grams  with  hot  water  and  determine  the 
nature  of  the  soluble  salts. 

Moisture. — Determine  on  2  grams  the  loss  in  weight  at  100  to 
105°  C. 

1  Method  of  P.  Drawe,  Zeitschriflfur  angew.  Chetnie,  Vol.  15,  p.  174  (1902). 

2  Scctts  Evolution  Method  1  following)  may  te  advantageously  used. 

3  Method  of  Copalle,  Ann.  chim.  anal,  appl..  Vol.  12,  p.  62  {1907). 


5o8  ENGINEERING    CHEMISTRY 

Insoluble. — Oxidize  i  gram  with  nitric  acid  of  40°  Baume  (spe- 
cific gravity  1.38),  at  first  cold,  then  hot.  Then  add  hydrochloric 
acid,  evaporate  to  very  small  volume,  dilute  with  hot  water,  filter, 
ignite  the  precipitate  which  represents  the  barium  sulphate,  cor- 
responding to  the  total  barium.  If  the  insoluble  exceeds  66  to 
68  per  cent,  it  is  necessary  to  prove  that  the  excess  is  not  due  to 
the  addition  of  kaolin. 

Total  Zinc. — Determine  as  oxide  by  precipitation  as  carbonate 
in  the  filtrate  from  the  insoluble.  When  more  than  traces  of 
iron,  alumina,  or  lime  are  present,  it  is  best  to  determine  the  zinc 
volumetrically. 

Sulphide  of  Zinc. — Add  a  slight  excess  of  hydrochloric  acid  to 
the  filtrate  from  the  zinc  carbonate  and  determine  the  sulphur  by 
precipitation  in  the  usual  manner.  This  sulphur  multiplied  by 
3.0383,  or  the  weight  of  barium  sulphate  (BaSO^)  multiplied  by 
0.41 741,  gives  the  zinc  sulphide. 

Oxide  of  Zinc. — Multiply  the  weight  of  the  zinc  sulphide  by 
0.83507  to  obtain  the  zinc  oxide  corresponding  to  the  sulphide. 
Subtract  this  from  the  total  zinc'  oxide  and  report  the  remainder 
as  zinc  oxide  (it  may  be  present  as  oxide  or  as  carbonate). 

Barium  Carbonate. — Digest  2  grams  with  boiling  dilute  hydro- 
chloric acid,  dilute  with  hot  water,  filter  from  the  insoluble  and 
determine  the  barium  in  the  filtrate  by  precipitation  with  sulphuric 
acid.  The  weight  of  the  barium  sulphate  multiplied  by  0.84548 
gives  the  barium  soluble  in  the  acid  calculated  as  carbonate. 

Barium  Sulphate. — Subtract  the  barium  sulphate  corresponding 
to  the  carbonate  from  the  total  barium  sulphate. 

Sulphide  may  be  determined  directly  by  Scott's^  evolution 
method,  using  0.5  to  i  gram  of  pigment,  mixing  in  evolution  flask 
with  zinc  and  water,  running  in  HCl  from  separatory  funnel  and 
absorbing  the  HoS  in  alkaline  lead-nitrate  solution.  Filter  off  the 
PbS,  dissolve  in  hot  dilute  HNO3  and  determine  the  lead  as 
PbSO,  or  PbCrO,.    Calculate  to  ZnS  (PbS04Xo.32i7). 

Carbon  Dioxide. — Carbon  dioxide  may  be  determined  directly 
by  evolution  method  by  grinding  i  gram  of  sample  with  excess 

1  Scott,  "  White  Paints  and  Painting  Materials,"  p.  257. 


ENGINEERING    CHEMISTRY  509 

of  potassium  dichromate  (dry  salt)  ;  transfer  to  flask,  add  50  cc. 
of  water  and  run  in  H2SO4  (1:1)  from  separatory  funnel,  ab- 
sorbing CO2  in  KOH,  soda  lime  or  Ba(OH)2  solution.  A  tube 
containing  KMnO^  solution  or  acidified  CuSO^  solution  may  be 
placed  in  train  as  a  precaution. 

Cai^cium  Pigments. 
Whiting,  Paris  White,  Spanish  White,  and  Chalk. 

Whiting,  Paris  white,  Spanish  white,  and  chalk  are  the  natural 
and  artificial  forms  of  calcium  carbonate. 

Moisture. — Heat  2  grams  of  sample  in  an  air-bath  at  105°  C. 
for  2  hours.    Loss  in  wight  is  considered  as  moisture. 

Loss  of  Ignition. — Ignite  i  gram  over  blast  lamp  to  constant 
weight. 

Complete  Analysis. — Boil  2  grams  of  the  sample  in  a  covered 
vessel  with  30  cc.  of  HCl  (1:1)  and  a  few  drops  of  HNO3 ;  wash 
off  cover  and  evaporate  to  dryness,  take  up  with  a  little  HCl  and 
about  100  cc.  of  hot  water;  boil,  filter,  wash  with  hot  water,  ignite 
and  weigh  insoluble  matter.  Insoluble  should  consist  of  silicious 
matter.  Test  insoluble  for  BaSO^.  Heat  filtrate  from  insoluble 
to  boiling,  having  added  more  HCl  in  order  to  form  sufficient 
NH4CI  to  hold  magnesia  in  solution,  and  add  NH4OH  in  very 
slight  excess,  heat  a  few  minutes,  filter,  wash  with  hot  water, 
ignite  and  weigh  Al203+Fe203(-f-Ti02+P205).  It  is  best  to  re- 
dissolve  this  precipitate  in  hot  dilute  HCl  and  reprecipitate  with 
NH4OH.  (If  manganese  is  present,  it  may  be  precipitated  in  the 
united  filtrates  from  Al  and  Fe  by  H2S  and  NH4OH.)  Unite 
the  filtrates  and  make  up  to  a  definite  volume,  mix  and  take  an 
aliquot  corresponding  to  0.5  gram  of  sample;  dilute  if  necessary, 
heat  to  boiling  and  add  slowly  30  cc.  of  a  saturated  ammonium- 
oxalate  solution,  let  stand  on  steam  bath  i  to  2  hours;  filter,  re- 
dissolve  precipitate  in  dilute  HCl,  dilute,  add  10  cc.  of  ammonium- 
oxalate  solution  and  NH4OH  till  alkaline,  let  stand  on  steam  bath 
I  or  2  hours ;  filter,  wash  with  hot  water  till  free  from  chlorides. 
The  precipitate  may  be  ignited  to  constant  weight  in  a  platinum 
crucible  over  a  Meker  burner  and  the  CaO  weighed  as  such,  or  the 
CaO  may  be  determined  volumetrically  as  follows : 


5IO  ENGINEERING    CHEMISTRY 

The  precipitate  of  calcium  oxalate  must  be  washed  till  lo  cc. 
of  the  washings  plus  0.5  cc  of  H^SO^  heated  to  70°  C.  do  not  de- 
colorize I  drop  of  about  N/io  KMn04  solution.  The  beaker  in 
which  precipitation  was  made  is  placed  under  funnel,  apex  of 
filter  is  pierced  with  stirring  rod  and  the  precipitate  washed  into 
beaker;  then  pour  hot  dilute  HgSO^  (1:4)  over  paper,  wash  with 
hot  water,  add  about  30  cc.  of  the  dilute  H^gSO^  (1:4),  dilute  to 
about  250  cc,  heat  to  80  to  90°  C,  and  titrate  with  about  N/io 
KMnO^  (Fe  value  of  KMnO^  X  0.50206  —  CaO  value).  Evap- 
orate the  united  filtrates  from  the  calcium  oxalate  to  about  200 
cc. — should  any  magnesium  oxalate  separate,  dissolve  it  by  adding 
a  little  HCl — add  5  cc.  of  NH4OH,  heat  to  boiling  and  add  10 
to  15  cc.  of  saturated  Na^aHPO^  solution.  Add  a  few  cubic  centi- 
meters more  of  NH^OH,  cool  in  ice  water  with  vigorous  stirring. 
Let  stand  2  to  4  hours,  filter  on  a  gooch  crucible,  wash  with  2 
per  cent.  NH4OH  containing  a  little  NH4NO3;  ignite  gently  at 
first  and  finally  at  a  bright  red  for  5  or  10  minutes,  cool  and  weigh 
as  magnesium  pyrophosphate.  Calculate  to  MgO.  If  magnesium 
is  high,  or  for  very  accurate  work,  the  NH4MgP04  should  be 
redissolved  in  dilute  HCl  and  the  Mg  reprecipitated  as  above.  If 
MgO  is  very  low,  it  may  be  necessary  to  destroy  the  ammonium 
salts  in  the  filtrate  from  the  calcium  oxalate  before  precipitating 
the  MgO.  This  may  be  effected  by  evaporating  to  dryness  with 
excess  of  HNO3,  taking  up  with  HCl  and  water,  filtering  and 
proceeding  as  above. 

Carbon  Dioxide. — Determined  by  evolution  method  as  under 
basic  carbonate  of  lead. 

Total  Soluble  Sulphates. — Determined  as  under  gypsum. 

Alkalinity. — Alkalinity  is  due  to  free  lime  or  possibly  to  sodium 
or  potassium  compounds.  Boil  2  grams  of  the  sample  for  5 
minutes  with  100  cc.  of  water,  filter,  add  phenolphthalein.  If  a 
red  color  develops,  free  lime  may  be  assumed  to  be  present. 
Titrate  with  N/io  acid. 

Gypsum,  Terra  Alba,  Plaster  of  Paris. 

Gypsum  is  a  natural  hydrated  calcium  sulphate,  CaS04.2H20; 
terra  alba  is  a  fairly  pure  grade  of  raw  gypsum;  plaster  of  Paris 


e;ngine;e:ring  chemistry  511 

is  a  calcined  or  dehydrated  calcium  sulphate — CaS04^H20. 
There  is  also  a  precipitated  calcium  sulphate  used  as  a  basis  for 
aniline  lakes, 

A  microscopic  examination  may  be  of  importance. 

Moisture. — Dry  2  grams  in  vacuum  desiccator  over  HgSO^  to 
constant  weight. 

Combined  Water  and  Moisture. — Heat  i  gram  of  the  sample  in 
a  covered  porcelain  crucible  on  an  asbestos  plate  for  15  minutes, 
then  heat  bottom  of  crucible  dull  red  for  10  minutes  over  a  Bun- 
sen  burner,  remove  cover  and  heat  for  30  to  40  minutes  at  a 
slightly  lower  temperature.  Cool  and  weigh  rapidly.  Repeat  to 
constant  weight. 

Combined  water  and  moisture  may  also  be  determined  by  heat- 
ing in  air  bath  at  200°  C.  to  constant  weight. 

Soluble  and  Insoluble. — Boil  2  to  3  grams  of  the  sample  with 
20  cc.  of  concentrated  HCl,  a  few  drops  of  HNO3,  ^^^  about  50 
cc.  of  water;  evaporate  to  dryness,  boil  residue  repeatedly  with 
10  per  cent.  HCl;  filter,  wash  with  hot  water,  ignite  and  weigh 
insoluble  matter.  Test  for  BaS04 — make  filtrate  up  to  500  cc. 
and  mix.  To  200  cc.  add  about  2  grams  of  NH4CI  and  NH4OH 
till  slightly  alkaline,  heat  till  only  faint  odor  of  NH4OH  remains, 
let  settle,  filter,  wash  with  hot  water,  ignite  and  weigh 
AloOg+Fe^Og.  Heat  filtrate  from  Al  and  Fe  to  boiling  and 
add  about  40  cc.  of  saturated  ammonium  oxalate  solution,  let 
stand  on  steam  bath  2  hours;  filter,  redissolve  precipitate  in  hot 
dilute  HCl,  add  10  cc.  of  ammonium  oxalate  solution  and  NH4OH 
till  alkaline,  let  stand  i  hour  on  steam  bath ;  filter,  wash  with  hot 
water  till  free  from  soluble  oxalates  (see  test  under  whiting), 
and  proceed  as  under  whiting,  titrating  with  KMn04.  The 
united  filtrates  from  the  lime  are  evaporated  and  MgO  deter- 
mined as  under  whiting. 

Soluble  Sidphate. — Make  200  cc.  of  the  filtrate  from  the  in- 
soluble slightly  alkaline  with  NH4OH,  then  acid  with  HCl,  heat 
to  boiling  and  add  20  cc.  of  hot  10  per  cent.  BaCl2  solution,  stir 
well.  Let  stand  at  least  i  hour  on  steam  bath;  filter,  wash  with 
hot  water  till  washings  give  no  test  for  CI  with  AgNOg,  ignite. 


512  e:nginee)ring  chemistry 

cool  and  weigh  BavSO^.  For  very  accurate  work,  the  weighed 
BaSO^  should  be  purified  by  treating  with  dilute  HCl,  filtering, 
washing,  igniting  and  again  weighing. 

Carbon  Dioxide. — Determined  by  evolution,  weighing  in  soda 
lime,  KOH  bulb  or  as  BaCOg. 

Quicklime  and  Slaked  or  Hydrated  Lime. 

Quicklime  (CaO),  and  slaked  or  hydrated  lime  (Ca(OH)2), 
are  used  in  the  preparation  of  cold  water  paints,  for  example, 
whitewash.    These  materials  may  be  examined  as  under  whiting. 

Strontia  white,  SrS04,  and  strontianite,  SrCOg,  occur  only  in 
small  quantities  and  are  rarely  met  with  in  paint  analysis.  In  the 
usual  methods^  of  analysis  any  strontium  present  is  weighed  with 
the  CaO  or  reported  as  BaSO^  when  insoluble. 

Barium  Pigments. 
Barytes  or  Barite. 

Barytes  or  barite  is  a  natural  sulphate  of  barium ;  blanc  fixe  is 
precipitated  barium  sulphate.  Being  one  of  the  cheapest  white 
pigments,  this  material  is  seldom  adulterated.  It  should  be 
white,  well-ground  and  contain  not  less  than  95  per  cent,  of 
BaS04.  A  microscopic  examination  can  be  made  with  advantage 
to  determine  uniformity  of  grinding,  size  and  angularity  of  par- 
ticles, amorphous  or  crystaline.  Miscibility,  opacity,  specific 
gravity,  volume,  whiteness  of  color,  together  with  microscopic 
study  probably  give  more  information  than  chemical  analysis. 
However,  the  following  method  may  be  used : 

Moisture. — This  equals  the  loss  in  weight  on  heating  2  grams 
of  the  sample  at  105°  C.  for  2  hours. 

Loss  on  Ignition. — Ignite  i  gram  of  sample  for  30  minutes  (to 
constant  weight).  Loss  may  be  due  to  organic  matter,  free  and 
combined  water  and  CO,2.    Report  as  ''loss  on  ignition." 

Insoluble. — Boil  i  gram  with  HCl  (i  13),  evaporate  to  dry- 
ness, moisten  with  HCl,  add  water,  boil,  filter,  wash  with  hot 
water,  ignite  in  platinum  crucible  if  previous  qualitative  exam- 

1  For  methods    see    Bulletin    No.  422,    U.    S    Geological    Survey  ;    Treadwell-Hall. 
Analytical  Chemistry,"  etc. 


DNGINEJERING   CHKMISTRY  513 

ination  has  determined  the  absence  of  lead  or  other  easily  reduced 
metals.  Weigh  insoluble  and  treat  with  HgSO^  and  hydrofluoric 
acids  in  usual  manner,  evaporate,  ignite  and  weigh,  loss  in  silica ; 
residue  should  be  BaS04.  The  residue  may  be  fused  with 
Na2C03,  taken  up  with  hot  water,  acidified  with  HCl,  the  BaS04 
filtered  off,  washed,  and  ignited.  If  weight  so  obtained  differs 
materially  from  that  of  residue  from  hydrofluoric  acid  treat- 
ment, examine  last  filtrate  for  Al,  Fe,  Ca  and  Mg  that  may  have 
remained  as  residue  from  silicates. 

Alumina,  Iron  Oxide,  etc. — Add  NH^OH  to  the  filtrate  from 
the  total  insoluble,  boil,  filter,  wash,  ignite  and  weigh  as 
FC2O3  +  AI2O3.    In  filtrate  determine  Ca  and  Mg  as  in  gypsum. 

Soluble  Sulphate. — Boil  i  gram  with  20  cc.  of  concentrated 
HCl,  dilute  to  200  cc.  with  hot  water,  boil,  filter,  wash,  add 
NH4OH  to  filtrate  till  just  alkaline,  make  just  acid  with  HCl, 
boil,  add  10  per  cent.  BaCl^  solution  and  weigh  BaSO^  in  usual 
manner.  Calculate  to  CaSO^.  If  carbonates  are  present,  cal- 
culate the  remaining  CaO  to  CaCOg.  Any  excess  of  CaO  is  re- 
ported as  CaO. 

Carbon  Dioxide. — Determine  by  evolution  method  as  given 
under  basic  carbonate  of  lead. 

Barium  Carbonate. — If  present,  it  may  be  precipitated  in  first 
filtrate  before  determining  Al,  Fe,  etc.,  by  adding  10  per  cent, 
ammonium  sulphate  solution  containing  a  little  free  H2SO4,  fin- 
ally weighing  in  usual  manner  as  BaS04.  Any  excess  of  CO2 
over  the  barium  here  found  is  calculated  to  CaCOg. 

Iron. — If  in  \Qry  small  amount,  determine  color imetrically  as 
given  under  ''Method  for  Very  Small  Amounts  of  Iron." 

Water  Soluble. — This  test  is  sometimes  applied  to  blanc  fixe. 
Boil  5  grams  for  15  minutes  with  100  cc.  of  water,  filter  and 
wash.  Evaporate  filtrate  to  dryness  in  a  weighed  dish,  dry  30 
minutes  at  105°  C,  cool  and  weigh.  Test  for  sodium,  chlorine, 
CaS04,  etc. 

Witherite  (BaCO^). — This  may  be  examined  by  preceding 
methods. 

33 


514  e;ngine:ering  chemistry 

SiiviCA  Pigments. 
Silica  or  Silex. 

Silica  or  silex  (SiOo)  should  be  finely  ground  and  white. 

Moisture. — This  equals  the  loss  in  weight  on  heating  2  grams 
at  105°  C.  for  2  hours. 

Loss  on  Ignition. — Ignite  i  gram  to  constant  weight  in  a  plati- 
num crucible. 

Insoluble  Matter. — Boil  2  grams  of  the  sample  for  30  minutes 
with  50  cc.  of  HCl  (i  :  i),  add  50  cc.  of  water,  filter,  wash,  ignite 
and  weigh  insoluble  matter,  which  should  not  be  less  than  95  per 
cent.  This  insoluble  matter  is  treated  with  H2SO4  and  HF  in 
usual  manner,  loss  being  considered  as  silica,  SiOsi  the  residue 
is  fused  with  NaaCOg,  taken  up  with  water  and  HCl,  evaporated 
to  dryness,  any  SiO,2  (test  for  BaS04)  filtered  out  and  Al,  Fe, 
Ca,  and  Mg  determined  as  in  gypsum.  The  filtrate  from  the  in- 
soluble matter  (that  is,  the  soluble  portion)  is  evaporated  to  dry- 
ness, taken  up  with  HCl  and  water,  SiOg  filtered  out,  ignited  and 
weighed  as  usual.  In  filtrate  determine  Al,  Fe,  Ca,  and  Mg  as 
usual.  If  it  is  desired  to  determine  alkalies,  work  on  a  separate 
portion  by  the  method  of  Mr.  J.  Lawrence  Smith  as  in  Bulletin 
No.  422,  U.  S.  Geological  Survey. 

Iron  in  Small  Amounts. — See  "Method  for  Very  Small 
Amounts  of  Iron." 

China  Clay  and  Asbestine. 

Moisture. — Determined  as  under  silica. 

Loss  of  Ignition. — Determined  as  under  silica. 

Qualitative  tests  to  prove  that  the  materials  are  as  represented 
will  generally  suffice.  However,  a  complete  analysis  may  be  made 
as  follows : 

Fuse  I  gram  of  the  finely  powdered  sample  in  a  platinum  cru- 
cible with  about  10  grams  of  NasCOg  (requires  }^  to  i  hour) ; 
cool,  place  in  casserole,  digest  with  hot  water  till  mass  disinte- 
grates; acidify  with  HCl,  remove  crucible  and  lid,  washing  thor- 
oughly. Evaporate  to  dryness  on  steam  bath,  take  up  with  HCl 
and  hot  water,  filter,  wash  with  hot  water  till  free  from  CI ;  evap- 


ENGINEERING    CHEMISTRY  515 

orate  filtrate  to  dryness  and  treat  as  before,  filtering  on  a  separate 
paper.  Burn  the  two  silica  precipitates  together  in  a  platinum 
crucible,  finally  heating  over  Meker  burner  to  constant  weight; 
treat  with  H^SO^  and  HF  in  usual  manner,  loss  equals  SiOo.  If 
sample  contains  BaS04,  melt  from  fusion  should  be  digested  in 
hot  water  till  completely  disintegrated,  the  BaCOs  filtered  off  and 
washed  with  hot  water.  The  BaC03  ^^id  residue  are  dissolved  in 
hot  dilute  HCl,  the  Ba  precipitated  with  dilute  H,2S04,  and  the 
BaS04  determined  in  usual  manner.  Filtrate  from  this  BaS04 
is  added  to  first  filtrate,  acidified,  evaporated  for  silica,  etc.,  as 
described.  The  residue  from  SiOa  is  considered  as  Al^Og  and 
Fe20o,  the  Al  and  Fe  subsequently  obtained  being  ignited  in  same 
crucible.  In  filtrate  from  SiOa  make  a  double  precipitation  of 
Al  and  Fe  with  NH4OH  (having  sufficient  NH4CI  present  to  hold 
all  MgO  in  solution),  ignite  and  weigh  AI2O3  -|-  Fe^Og 
(TiOo  +  P^Og).  This  precipitate  may  be  fused  with  KHSO4, 
dissolve  in  dilute  H2SO4,  the  iron  reduced  (H2S  followed  by 
CO2)  and  titrated  with  KMNO4.  In  united  filtrates  from  Al 
and  Fe,  manganese  may  be  precipitated  with  H^S  and  NH4OH 
and  weighed  in  usual  way.  Expel  HoS  and  determine  CaO  and 
MgO  as  usual. 

Determine  alkalies  on  a  separate  portion  by  the  method  of  Mr. 
J.  Lawrence  Smith. 

Carbon  Dioxide. — Determined  by  evolution  method,  weighing. 

Soluble  Sulphates. — Boil  i  gram  with  20  cc.  of  HCl  (1:1) 
and  100  cc.  of  water,  filter,  wash.  Add  NH4OH  till  just  alkaline, 
HCl  till  acid  and  precipitate  with  BaClg  in  usual  manner. 

Asbestine  is  often  treated  with  HCl  as  under  silica,  the  soluble 
and  insoluble  portions  being  analyzed  separately. 

Analysis  of  Red  Lead.^ 

Approximate  formula,  Pb304  (probably  PbO,2.2PbO). 

Apparent  gravity  and  true  specific  gravity  determined  as  per 
methods  under  white  pigments. 

Fineness. — Wash  10  grams  with  water  through  No.  21  silk 
bolting  cloth,  dry  and  weigh  residue. 

1  This  includes  orange  mineral. 


5l6  ENGINEERING   CHEMISTRY 

Moisture. — Dry  2  grams  of  the  sample  for  2  hours  at  105°  C. 
The  loss  in  weight  is  considered  as  moisture. 

Organic  Color. — Boil  2  grams  of  the  sample  with  25  cc.  of  95 
per  cent,  ethyl  alcohol,  let  settle,  decant  off  the  supernatant  liquid ; 
boil  residue  with  water,  decant  as  before  and  boil  residue  with 
very  dilute  NH4OH.  If  either  the  alcohol,  water  or  NH^OH  is 
colored,  organic  coloring  matter  is  indicated. 

Total  Lead  and  Insoluble  Matter. — Treat  i  gram  of  the  sample 
with  15  cc.  of  HNO3  (1:1)  and  sufficient  hydrogen  dioxide  to 
dissolve  all  Pb02  on  warming.  If  any  insoluble  matter  is  present 
add  25  cc.  of  water,  boil,  filter  and  wash  with  hot  water.  In- 
soluble contains  free  SiO^  and  should  be  examined  for  BaS04 
and  silicates,  if  appreciable.  To  original  solution  or  filtrate  from 
insoluble,  add  20  cc.  of  concentrated  H2SO4  and  evaporate  to 
SO3  fumes;  cool,  add  150  cc.  of  water  and  150  cc.  of  95  per  cent, 
ethyl  alcohol,  let  stand  cold  2  hours,  filter  on  a  gooch  crucible, 
wash  with  95  per  cent,  alcohol,  dry  at  105  to  110°  C.  and  weigh  as 
PbSO^.  Calculate  to  PbO.  Red  lead  is  rarely  adulterated,  but 
should  sample  contain  soluble  barium  compounds,  the  PbSO^  ob- 
tained above  will  contain  BaSO^.  In  this  case,  digest  above  pre- 
cipitate with  acid  ammonium  acetate  solution,  filter  off  BaSOi, 
wash,  ignite  and  weigh  BaS04.  Calculate  to  BaO  or  BaCOg. 
In  filtrate,  determine  the  lead  as  PbSO^  or  PbCr04.  If  sample 
contains  significant  amounts  of  calcium  or  magnesium,  the 
HN03~H202  solution  is  boiled  till  all  lead  is  converted  into  ni- 
trate and  then  lead  determined  as  PbCr04.  If  Ca  and  Mg  are  to 
be  determined,  separate  lead  as  PbS  and  proceed  as  under  basic 
sulphate  of  lead  in  presence  of  these  metals. 

Determination  of  Lead  Peroxide  {PbO 2)  and  True  Red  Lead 
(F^304.)— (Method  of  DiehP  modified  by  Topf^— not  applicable 
when  substances  are  present,  other  than  oxides  of  lead,  that  lib- 
erate iodine  under  conditions  given.) 

Weigh  I  gram  of  finely  ground  sample  into  a  200-cc.  Erlenmeyer 
flask,  add  a  few  drops  of  distilled  water  and  rub  the  mixture  to  a 
smooth  paste  with  a  glass  rod  flattened  on  end.     Mix  in  a  small 

2  Ding.  Polyt.  Jour.,  Vol.  246,  p.  196. 

3  Zeitschrifl  fur  analysche  Chemie,  Vol.  26,  p.  296. 


ENGINEERING    CHEMISTRY  517 

beaker  30  grams  of  C.  P.  ''Tested  Purity"  crystallized  sodium 
acetate,  2.4  grams  of  C.  P.  potassium  iodide,  10  cc.  of  water  and 
10  cc.  of  50  per  cent,  acetic  acid ;  stir  until  all  is  liquid,  warming 
gently;  if  necessary  add  2  to  3  cc.  of  H^^O,  cool  to  room  tempera- 
ture and  pour  into  the  flask  containing  the  red  lead.  Rub  with  the 
glass  rod  until  nearly  all  the  red  lead  has  been  dissolved;  add 
30  cc.  of  water  containing  5  or  6  grams  of  sodium  acetate,  and 
titrate  at  once  with  decinormal  sodium  thiosulphate,  adding  the 
latter  rather  slowly  and  keeping  the  liquid  constantly  in  motion  by 
whirling  the  flask.  When  the  solution  has  become  light  yellow, 
rub  any  undissolved  particles  up  with  the  rod  until  free  iodine  no 
longer  forms,  wash  off  rod,  add  the  sodium  thiosulphate  solution 
until  pale  yellow,  add  starch  solution  and  titrate  until  colorless, 
add  decinormal  iodine  solution  until  blue  color  is  just  restored  and 
subtract  the  amount  used  from  the  volume  of  the  thiosulphate  that 
has  been  added. 

Calculation. — The  iodine  value  of  the  sodium  thiosulphate  solu- 
tion multiplied  by  0.94193  =  PbO^ ;  the  iodine  value  multiplied  by 
2.69973  =  Pb304 ;  the  PbOg  value  multiplied  by  2.86616  =  Pb304. 

The  Sodium  Thiosulphate  Solution  (Decinormal). — Dissolve 
24.83  grams  of  C.  P.  sodium  thiosulphate,  freshly  pulverized  and 
dried  between  filter  paper,  and  dilute  with  water  to  i  liter  at  the 
temperature  at  which  the  titrations  are  to  be  made.  Solution  best 
made  with  well-boiled  HgO  free  from  COg,  or  let  stand  8  to  14 
days  before  standardizing.  Standardize  with  pure,  resublimed 
iodine,  as  described  in  Treadwell-Hall,  Analytical  Chemistry, 
Vol.  II,  p.  602  (1910),  and  also  against  pure  potassium  iodate — 
the  two  methods  of  standardization  should  agree  within  o.i  per 
cent,  on  iodine  value. 

Starch  Solution. — Two  to  3  grams  of  potato  starch  are  stirred 
up  with  100  cc.  of  I  per  cent,  salicylic  acid  solution,  and  the  mix- 
ture is  boiled  till  starch  is  practically  dissolved,  then  diluted  to 
I  liter.i 

1  Lead  Peroxide. — If  sample  contains  no  appreciable  amount  of  nitrate  (nitrate  has  no 
effect  on  method),  leach  out  water  soluble  matter  as  below,  dry  residue  and  determine 
PbO.2  as  above,  calculating  to  basis  of  original  sample. 


5l8  ENGINEERING   CHEMISTRY 

Zinc. — If  an  appreciable  amount,  determine  in  filtrate  from 
total  lead  as  per  methods  under  zinc  white,  evaporating  off  the 
alcohol. 

Water  Soluble. — Digest  lo  grams  of  sample  with  200  cc.  of 
hot  water  on  steam  bath  for  i  hour;  filter  on  an  11 -centimeter 
S.  &  S.  blue  ribbon  paper  and  wash  with  hot  water  till  no  residue 
is  left  on  evaporating  a  few  drops  of  the  washings.  Evaporate 
filtrate  to  dryness  on  steam  bath  in  a  weighed  dish,  dry  30  minutes 
at  105°  C,  cool  and  weigh.  Take  up  with  water  and  if  alkaline, 
titrate  with  o.i  normal  acid  and  methyl  orange;  calculate  to 
Na^COg.  Another  lot  of  water  soluble  matter  is  tested  for  ni- 
trates, nitrites,  carbonates,  sulphates,  sodium  and  lead. 

Total  Silica. — Digest  5  grams  of  the  sample  in  a  covered  cas- 
serole with  5  cc.  of  HCl  and  15  cc.  of  HNO3  (i  •  i)-  Evaporate 
to  dryness  to  dehydrate.  Cool,  treat  with  hot  water  and  HNO3, 
boil,  filter,  wash  with  hot  acid  ammonium  acetate  solution,  then 
dilute  HCl  and  finally  hot  water.  Ignite  and  weigh  as  Si02.  The 
residue  may  be  treated  with  H0SO4  and  HF  in  cases  of  doubt 
as  to  purity. 

Carbon  Dioxide. — Determined  by  evolution  method,  using  dilute 
HCl  and  stannous  chloride. 

Soluble  Sulphate. — Determined  as  under  basic  sulphate  of  lead. 

Iron  0.^i(/^.-— Determined  by  Schaeffer's  modification  of  Thom- 
son's calorimetric  method ;  or,  in  a  large  beaker,  treat  20  grams  of 
the  sample  with  20  cc.  of  water,  20  cc.  of  HNO3  (specific  gravity 
1.4)  and  3  cc.  of  formaldehyde  solution.  Warm  till  all  PbOg  is 
dissolved,  dilute  with  water,  warm,  filter  off  insoluble  and 
wash  with  hot  water.  Ignite  filter  and  insoluble,  evaporate  with 
H2SO4  and  hydrofluoic  acid.  To  filtrate  from  insoluble  add 
14  cc.  of  H2SO4  (i  :  i),  filter  off  PbSO^,  wash.  Residue  from 
HF  and  H2SO4  is  dissolved  in  HaSO^  and  added  to  filtrate  from 
PbS04 ;  dilute  to  500  cc.  and  determine  Fe  colorimetrically  in  an 
aliquot,  using  same  amounts  of  HNO3,  HoSO^  and  formaldehyde 
in  comparison  solution.    Calculate  to  FcgOs. 


ENGINEERING   CHEMISTRY  519 

Specifications  for  White  Lead  Issued  by  the  Navy 
Department,  March  1,  1915. 

Generai,. 

1.  \A'hite  lead  shall  be  furnished,  dry  or  in  oil,  as  specified,  and  shall 
conform  to  the  following  requirements : 

QUAUTY. 

2.  To  be  as  follows : 

(a)  White  Lead,  Dry. — The  pigment  shall  be  pure  hydrated  carbonate 
of  lead,  free  from  all  adulterants.  The  total  acetate  shall  not  be  in  excess 
of  the  equivalent  of  0.15  per  cent,  of  absolute  acetate  acid. 

(b)  White  Lead,  in  Oil. — To  be  of  the  same  quality  as  white  lead 
dry,  and  be  finely  ground  in  at  least  8.50  per  cent.,  by  weight,  of  pure  raw 
linseed  oil  in  accordance  with  the  latest  issue  of  Navy  Department  Speci- 
fications for  Raw  Linseed  Oil.  The  material  shall  not  contain  more  than 
0.50  per  cent,  of  moisture. 

Comparison  with  Standard  Sampee. 

3.  White  lead,  dry  and  in  oil,  shall  be  free  from  crystalline  structure 
and  be  equal  in  whiteness,  fineness,  opacity  or  body,  tinting  strength,  and 
covering  quality  to  the  standard  sample  of  white  lead,  samples  of  which 
may  be  obtained  by  application  to  the  construction  officer,  navy  yard,  New 
York,  N.  Y. 

Tinting  Test. 

4.  The  tinting  strength  required  in  paragraph  3  will  be  compared  to 
the  standard  sample  of  dry  white  lead  as  follows  :  Ten  grams  of  dry 
white  lead  will  be  thoroughly  ground  wuth  10  milligrams  of  dry  lampblack 
and  a  sufficient  weight  of  raw  linseed  oil  to  reduce  the  lead  to  a  paste 
form,  and  compared  with  equal  amounts  of  standard  white  lead,  dry 
lampblack,  and  linseed  oil  ground  in  the  same  manner.  Where  no  means 
are  at  hand  for  weighing  in  grams  and  milligrams,  larger  amounts  may 
be  used  in  the  same  proportion  as  indicated  above.  When  treated  as 
above  and  placed  alongside  of  the  standard  sample  on  a  glass  slide,  the 
tint  of  the  lead  under  test  shall  not  be  darker  than  that  of  the  standard 
sample. 

Note. — In  case  of  samples  of  white  lead  in  oil,  the  oil  will  be  extracted 
with  gasoline  or  some  equally  suitable  solvent,  so  that  the  tinting  test  can 
be  made  on  the  dry  pigments. 

Lead  white,  ground  in  oil,  is  a  common  form  in  the  market.  It 
visually  contains  about  8  per  cent,  of  raw^  linseed  oil,  and  has  an 
extended  use  among  painters,  as  it  readily  mixes  v\^ith  additional 
oil  and  turpentine  to  form  liquid  paint. 


520 


ENGINEERING    CHEMISTRY 


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So-called  when  below 95°  F.  flash.    The  familiar 
volatile  known  as  naphtha  or  painters'  spir- 
its.    On   eitlier  paraffine  or  asphaltum  ba.se. 
Boiling  point  i2o°-i50°  F. 

So-called  when  above  95°   F.   flash,  and  on  a 
paraffine  ba.se.     Evaporative,  value  about  35 
minutes    without    leaving    stain    on    paper. 
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r^o-called   when  above  95°  F.  .flash,  and  on  an 
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Practice    (allowed    by    State 
authorities  is  to  disregard 
presence  of  water  in  paint 
up  to  1.5  per  cent,  ot  the 
fluid  portion,  this  amount 
being    recognized  as  acci- 
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ess   of    manufacture.      All 
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in  the  fluid  portion    to  be 
stated  on  label. 

ENGINEERING   CHEMISTRY  523 

SCHEME  FOR  THE  ANALYSIS  OF  MIXED  CHROMATE  AND  SULPHATE 
OF  LEAD  (LEMON  CHROME)  NOT  GROUND  IN  Oil 

Pulverize  the  sample,  pass  through  a  loo-niesh  sieve  and  mix.  To  i  gram  in  a 
small  beaker,  add  hvdrochloric  acid  and  heat.  Any  insoluble  matter  (usually  barytes  as 
a  gross  adulteration)  is  to  be  filtered  out,  and  washed,  ignited  and  weighed. 

Lead.— One  g'am  is  treated  in  a  covered  casserole  with  25  cc.  concen'rated  sulphuric 
acid  and-heated  moderately  until  the  residue  is  perfectly  white  ;  cool,  diliite  with  50  cc. 
water  and  again  cool;  add  50  to  75  cc.  of  04  per  cent,  alcohol,  stir,  and  allow  to  stand  i 
hour.    Filter,  wash  well  with  alcohol,  dry,  ignite,  and  weigh  as  PbS04. 

Chromium  and  Sulphuric  Acid  (SO3).  —  Treat  i  gram  with  about  25  cc.  concentrated 
hydrochloric  acid,  boil,  dilute  to  100  cc.  and  while  hi.t  add  excess  of  ammonium  by. 
dfoxide  which  precipitates  the  chromium  and. the  greater  part  of  the  lead.  Boil  off  the 
excess  of  ammonia,  filter  and  wash  carefully  with  hot  water. 


1.  Precipitate  for  Cr.— Dissolve  in  dilute  HCl.  nearly  neutralize 
acid  with  NH4OH,  precipitate  Pb  with  HgS  gas  and  filter  into  a 
porcelain  dish. 


3.  Precipitate.— Pbs, 
reject. 


4.  Filtrate.— Boil  off  H2S  and  precipitate 
Cr  with  NH4OH  in  the  usual  manner.  Put 
the  moist  precipitate  and  filter  paper  into  i. 
crucible  and  ignite  carefully.  Weigh  as 
CroOa. 


.2.  Filtrate  for  SO3.— 
Acidify  with  HCl,  con- 
centrate, add  boiling 
solution  of  BaClo  drop 
by  drop  and  de  t  e  r- 
mine  SO3  as  usual. 


Occasionally  the  following  determinations  are  made : 

Water. — Hygroscopic.  Heat  ^  gram  at  105°  C.  in  an  air-bath 
to  constant  weight. 

Volatile  Matter. — Heat  i  gram  in  a  porcelain  crucible  to  low 
redness ;  loss,  less  water,  is  volatile  matter. 

Water  Extract. — (Acetates,  sulphates,  bichromates,  or  nitrates), 
indicating  imperfect  washing  in  manufacture.  Treat  3  grams 
with  six  successive  portions  of  25  cc.  each,  of  cold  distilled  water, 
decanting  and  filtering  each  time,  and  evaporate  the  filtrate  in  a 
platinum  dish  to  dryness  on  a  water-bath. 

Specifications  for  Chrome  (Yellow)  Issued  by  the 
Navy  Department,  August  2,  1915. 

1.  The  dry  pigment  shall  contain  at  least  98  per  cent.,  by  weight,  of 
normal  chromate  or  basic  chromate  of  lead. 

2.  When  required  in  paste  form,  the  pigment  .shall  be  finely  ground 
to  a  medium  stif?  paste  in  absolutely  pure,  well-settled,  and  perfectly 
clear  raw  linseed  oil  conforming  to  the  latest  issue  of  Navy  Department 
Specifications  for  Raw  Linseed  Oil.  Such  paste  shall  break  up  readily 
in  thinning  and  shall  be  free  from  grit,  adulterants,  and  all  impurities. 

3.  The  color,  shade,  tone,  fineness,  and  coloring  power,  determined 
by  assaying  with  white  zinc,  shall  be  equal  to  the  standard  sample. 


524  ENGINEJEJRING   CHEjMISTRY 

4.  Portions  of  the  standard  sample  referred  to  in  paragraph  3  may 
be  obtained  upon  appHcation  to  the  construction  officer's  offices  at  the 
various  navy  yards. 

Analysis  of  Mixed  Chromate,  Sulphate,  and  Carbonate  of  Lead.^ 

Analysis  made  same  as  in  scheme  for  lemon  chrome;  excess 
of  lead  is  to  be  calculated  to  white  lead,  2PbC03  +  PbH^Og. 

Analysis  of  Red  Chromate  of  Lead.^ 

For  the  lead  determination  take  i  grarn  in  a  covered  casserole, 
add  25  cc.  concentrated  nitric  acid,  heat  to  boiling,  and  while 
boiling,  add  }^  dozen  drops,  one  at  a  time,  of  alcohol,  by  means 
of  a  pipette;  boil  a  while  longer,  add  water,  and  all  of  the  chro- 
mate, if  it  is  pure,  will  be  found  in  solution. 

Without  this  alcohol  treatment  great  difficulty  will  be  experi- 
enced in  getting  the  chromate  into  solution;  with  it  it  is  easily 
accomplished.  Add  25  cc.  concentrated  sulphuric  acid,  evaporate 
to  white  fumes,  and  complete  the  analysis  as  described.  For  chro- 
mium and  sulphur  trioxide  determinations,  boil  off  alcohol  and 
proceed  as  previously  directed. 

The  Volumetric  Determination  of  Red  Lead. 

A  rapid  and  accurate  method  of  finding  the  amount  of  red  lead 
(PbgOi)  in  a  sample  of  red  lead.^ 
Solutions. — I   N/io  iodine  solution. 

2  Stannous   chloride   solution    (14.1   grams   SnCl^ 

to  1,000  cc.  H,20). 

3  Starch  solution. 

Tw^enty-five  cubic  centimeters  stannous  chloride  solution  are  ac- 
curately measured  into  a  lo-ounce  Erlenmeyer  flask.  Forty  cubic 
centimeters  hydrochloric  acid  are  added  and  the  whole  is  raised  to 
boiling.  Boil  i  minute,  add  100  cc.  cold  water,  washing  down 
the  sides  of  the  flask,  and  cool  rapidly.  Add  a  few  cubic  centi- 
meters of  starch  solution  and  run  in  from  a  burette  sufficient 

1  "  Analysis  of  Chrome  Paints,"  by  W.  I,.  Brown,  y.  Anal.  Chem..  1,  213-215. 

-  Known  by  various  names,  as  scarlet,  dark  or  basic  chromate  of  lead,  chrome  red, 
Chinese  red,  American  vermilion,  and  vermilion  substitute.  Formula:  2PbO.Cr03  or 
PbCr04  +  PbO. 

=*  Communicated  to  the  author  by  J.  H.  Wainwright,  Ph.  B.,  F.  C.  S. 


e;nginee)ring  chemistry  525 

iodine  solution  to  give  a  permanent  blue  color.  This  gives  the 
number  of  cubic  centimeters  or  iodine  solution  equivalent  of 
25  cc.  stannous  chloride  solution. 

Determination. — One  gram  red  lead  is  very  accurately  weighed, 
placed  in  an  Erlenmeyer  flask  and  moistened  with  water.  Run  in 
25  cc.  stannous  chloride  and  40  cc.  hydrochloric  acid.  Boil  until 
all  the  lead  is  in  solution.  Add  100  cc.  cold  water  and  cool  rap- 
idly. Add  a  few  cubic  centimeters  of  starch  solution  and  titrate 
with  iodine  to  a  permanent  blue  color.  The  difference  in  cubic 
centimeters  of  iodine  solution  used  in  the  blank  test  and  in  the 
determination  gives  the  number  of  cubic  centimeters  of  iodine  so- 
lution to  which  the  available  oxygen  in  the  red  lead  is  equivalent. 
(One  cubic  centimeter  of  N/io  iodine  solution  =  0.8  milligram 
oxygen. ) 

The  titration  should  be  performed  as  rapidly  as  possible  on 
account  of  the  action  of  the  acid  upon  the  starch  indicator. 

The  available  oxygen  multiplied  by  42.73  equals  the  percent- 
age of  red  lead. 

Specifications  in  Part  for  Red  Lead,  Dry,  Issued  by  the 
Navy  Department,  April  1,  1915. 

1,  The  dry  pigment  must  be  of  the  best  quality,  free  from  all  adulter- 
ants, and  contain  at  least  94  per  cent,  of  true  red  lead  (Pb304) — equiva- 
lent to  32.8  per  cent,  of  lead  peroxide  (PbOa) — the  balance  to  be  prac- 
tically pure  lead  monoxide  (PbO).  It  must  contain  less  than  o.i  per  cent, 
of  metallic  lead,  and  to  be  of  such  fineness  that  no  more  than  0.5  per  cent, 
remains  after  washing  with  water  through  a  No.  21  silk  bolting  cloth 
sieve.  It  must  be  of  good  bright  color  and  be  equal  to  the  standard 
sample  in  freedom  from  vitrified  particles  and  in  other  respects. 

2.  When  mixed  with  pure  linseed  oil,  pure  turpentine,  and  Japan 
drier,  as  per  standard  formula,  viz. : 

Red  lead,  dry  pounds  20 

Raw  linseed  oil   pints  5 

Petroleum  spirits    gills  2 

Drier    do  2 

and  applied    to  a  srnooth  vertical  iron  surface  it  must  dry  solidly  without 
running,  streaking  or  sagging. 


526 


ENGINEERING   CHEMISTRY 


Analysis  of  Chrome  Green. 

(Composed  of  yellow  chromate  of  lead,  Prussian  blue  and  lead  sulphate) 

To  I  gram  of  sample  add  25  cc.  HCl.  heat  to  boiling  several  minutes,  add  water,  allow 
to  stand  10  minutes,  then  filter  and  wash  thoroughly  with  hot  water. 


1.  Residue. —  Prus- 
sian blue  (plus  bary- 
les  if  present).  Dry 
and  ignite  to  Fe203,  if 
barytes  is  not  present. 

Weight  multiplied 
by  2.21  equals  per 
cent.  Prussian  blue. 


2.  Filtrate.— Nearly  neutralize  with  NH4OH,  leaving,  however, 
the  solution  .slightly  iicid.  Pass  HoS  gas  through  till  Pb  is  all 
precipitated.     Filler  and  wash. 


3.  Precipitate,  PbS.— 
Dissolve  on  filter  with 
hot  dilute  H  NO3  and 
boil  the  solution.  Filter 
from  collected  S  and 
bring  filtrate  of  Pb- 
(N03)2  to  small  bulk, 
with  several  additions 
of  H0SO4  Evaporate 
nearly  to  dryness,  cool, 
idd  water  and  alcohol, 
filter,  wash  and  weigh 
as  PbSOv 


4.  Filtrate.  —  For  Cr  (and  Fe),  boil  off 
HoS  add  NH4OH,  in  slight  excess,  boil  this 
off  and  wash  the  Cr3(OH)6  and  Fe2(OH)6. 
as  customary.  Weigh  precipitate  as  Cr^- 
O3  -t  Fe203.  After  the  weight  is  obtained, 
mix  with  one  part  KNO3  and  three  parts 
\a2C03;fuse  in  platintim  crucible  to  clear 
fusion,  cool,  boil  with  water,  filter  and 
wash. 


5.  Residue. 
Dry,  Ignite,  and 
weigh  as  Fe203, 
if  it  is  wanted 
as  a  check. 


6.  Filtrate,  for  Cr.  — 
Make  acid  with  HCl.  Re- 
duce with  alcohol.  Preci- 
pitate with  NH^OH  in 
glazed  porcelain  dish.  If 
the  weight  of  Cr203  isvfry 
nearly  the  same  as  before, 
then'there  has  been  no  Fe 
extracted  from  the  Prus- 
sian bjue  by  the  acid 
treatment.  'Some  varie- 
ties are  affected  bv  this, 
others  not.  If  the  weight 
is  less  than  the  original, 
deduct  it  from  same.  I  he 
result  is  Fe203.  which  is 
also  to  be  calculated  to 
Prussian  blue  and  added 
to  the  other. 


Chrome  green,  in  which  the  coloring  matter  is  CrgOg,  is  seldom 
found  in  the  market  pure.  Usually  it  contains  from  20  per  cent, 
to  75  per  cent,  of  barium  sulphate. 

Specifications  for  Chrome  Green,  Issued  by  the  Navy 
Department,  June  1,  1914. 

Composition  of  Pigment. 

1.  The  pigment  to  contain  at  least  98  per  cent,  by  weight  of  pure 
lemon  chrome  and  Chinese  blue,  which  mixture  shall  not  contain  more 
than  10  per  cent,  by  weight  of  lead  sulphate. 

Pigment  Ground  in  On.. 

2.  When  required  in  paste  form  the  pigment  shall  be  finely  ground  to 
a  medium  stiff  paste  in  absolutely  pure,  well-settled,  and  perfectly  clear 
raw  linseed  oil  conforming  to  the  latest  issue  of  Navy  Department  Speci- 
fications for  Raw  Linseed  Oil.  Such  paste  shall  break  up  readily  in 
thinning  and  shall  be  free  from  grit,  adulterants,  and  all  impurities. 


Kngine:ering  chemistry  527 

Physicai,  Properties. 

3.  The  color,  shade,  tone,  fineness,  and  coloring  power,  determined 
by  assaying  with  French  white  zinc  in  oil,  shall  be  equal  to  the  standard 
sample,  which  may  be  seen  at  the  general  storekeepers'  offices  in  the 
various  navy  yards. 

Packing  and  Marking. 

4.  To  be  delivered,  unless  otherwise  specified,  in  5-pound  friction- 
top  cans  and  25-pound  soldered-top  tins  as  required,  properly  labeled  with 
the  name  of  the  material,  quantit}^,  and  the  name  of  the  manufacturer. 
The  25-pound  cans  to  be  provided  with  bails. 

Deliveries. 

5.  Material  to  be  boxed  in  quantities  of  100  pounds  each  in  boxes 
made  of  sound  wood  %  inch  thick,  planed  on  the  outside,  and  marked 
with  the  name  of  the  material,  quantity,  name  of  contractor,  and  requisi- 
tion or  contract  number  under  which  delivery  is  made. 

Basis  oe  Payment. 

6.  Payment  will  be  based  on  net  weight,  and  net  weight  only  should 
be  delivered. 

As  an  example  of  specifications  for  a  compound  chrome  paint, 
the  following  is  given : 

Pennsylvania  Railroad  Company — Motive  Power  Department. 
Specifications  for  Cabin  Car  Color. 

The  standard  cabin  car  color  is  the  pigment  known  as  scarlet  lead 
chromate.  It  is  always  purchased  dry.  The  material  desired  under  this 
specification  is  the  basic  chromate  of  lead  (PbCr04PbO),  rendered  bril- 
liant by  treatment  with  sulphuric  acid,  and  as  free  as  possible  from  all 
other  substances. 

The  theoretical  composition  of  basic  lead  chromate  is  nearly  59.2  per 
cent,  of  the  normal  lead  chromate,  and  40.8  per  cent,  of  lead  oxide,  but 
in  the  commercial  article  it  is  found  that  a  portion  of  the  sulphuric  acid 
added  to  brighten  the  color  remains  in  combination  apparently  with  the 
normal  lead  chromate,  slightly  increasing  the  percentage  of  this  constituent. 

Samples  showing  standard  shade  will  be  furnished  on  application, 
and  shipments  must  not  be  less  brilliant  than  sample.  The  compaiison  of 
sample  from  shipment  with  the  standard  shade,  may  be  either  dry  or  by 
mixing  both  samples  with  oils. 

Shipments  of  cabin  car  color  will  not  be  accepted  which — 

1.  Contain  barytes  or  any  other  adulterant. 

2.  Show  on  analysis  less  than  57  per  cent,  or  more  than  60  per  cent, 
of  normal  lead  chromate,  including  the  sulphuric  acid  combined  as  above 
stated. 


528  ENGINEERING   CHEMISTRY 

3.  Show  on  analysis  less  than  38  per  cent,  or  more  than  42  per  cent. 
lead  oxide,  in  addition  to  the  lead  oxide  in  the  normal  lead  chromate. 

4.  Vary  from  standard  shade. 

Specifications  for  Indian  Red,  Issued  by  the  Navy  Department, 
August  2,  1915. 

The  dry  pigment  to  contain  at  least  95  per  cent.,  by  weight,  of  oxide 
of  iron  (FeaOs)  and  be  free  from  alkali,  lakes,  and  from  more  than 
i/io  of  I  per  cent.,  by  weight,  of  sulphur  (S)  in  any  form  other  than 
calcium  sulphate. 

When  required  in  paste  form,  the  pigment  shall  be  finely  ground  to 
a  medium  stiff  paste  in  absolutely  well-settled  and  perfectly  clear  raw 
linseed  oil  conforming  to  the  latest  issue  of  Navy  Department  Specifica- 
tions for  Raw  Linseed  Oil.  Such  paste  shall  break  up  readily  in  thinning 
and  shall  be  free  from  grit,  adulterants,  and  all  impurities. 

The  color,  shade,  tone,  fineness,  and  coloring  power,  determined  by 
assaying  with  white  zinc  in  oil,  shall  be  equal  to  the  standard  sample. 

Portions  of  the  standard  sample  referred  to  in  paragraph  3  may  be 
obtained  upon  application  to  the  construction  officer's  offices  at  the  various 
navy  yards. 

Unless  otherwise  specified  the  material  shall  be  delivered  in  soldered- 
top  tins  containing  5  and  10  pounds  each,  as  required.  Tins  to  be  labeled 
with  the  name  of  the  material,  the  quantity,  and  the  name  of  the  manu- 
facturer. Deliveries  to  be  boxed  in  quantities  of  100  pounds  in  boxes 
made  of  wood  %  inch  thick,  planed  on  the  outside  and  marked  with  the 
name  of  the  material,  the  name  of  the  contractor,  the  quantity  contained, 
and  the  requisition  or  contract  number  under  which  delivery  is  made. 

Specifications  for  White  Zinc,  Issued  by  the  Navy  Department, 
March  10,  1910. 

1.  American  Process. — The  dry  pigment  must  contain  at  least  98  per 
cent.,  by  weight,  of  oxide  of  zinc,  not  more  than  2/10  per  cent.,  by  weight, 
of  sulphur  in  any  form,  and  be  of  best  quality  known  as  "XX." 

2.  French  Process. — The  dry  pigment  must  contain  at  least  99  per 
cent.,  by  weight,  of  oxide  of  zinc  and  not  more  than  i/io  per  cent,  by 
weight,  of  sulphur  in  any  form,  and  to  be  of  maximum  whiteness  as  com- 
pared with  the  standard  sample. 

3.  The  requisition  will  state  specifically  which  kind  is  desired. 

4.  The  pigment  must  be  of  the  best  quality,  finely  ground  in  abso- 
lutely pure,  well  settled  and  perfectly  clear  raw  Hnseed  oil  of  the  best 
quality  only  to  a  medium  stiff  paste,  which  will  break  up  readily  in  thin- 
ning, and  must  be  free  from  grit,  adulterants,  and  all  impurities. 

5.  The  whiteness  and  fineness  must  be  equal  to  the  standard  sample. 
Any  indication  of  bluing  will  be  sufficient  cause  for  rejection. 


I^NGINEERING   CHE;miSTRY  529 

6.  Unless  otherwise  specified,  the  material  is  to  be  delivered  in  fric- 
tion-top cans  of  the  required  size  or  sizes,  properly  labeled  with  the  name 
of  the  material,  the  capacity  of  the  can,  and  the  name  of  the  manufac- 
turer. Cans  of  5  pounds  capacity  and  over  must  be  provided  with  bails ; 
net  weight  to  be  delivered. 

7.  The  material  is  to  be  delivered  boxed  in  quantities  of  100  pounds 
each ;  the  boxes  to  be  made  of  %-inch  new  pine,  planed  on  both  sides, 
and  properly  labeled  with  the  name  of  the  material,  the  name  of  the 
manufacturer,  and  the  contract  and  requisition  number  on  which  the 
material  was  purchased. 

Specifications  for  Brown  Zinc,  Issued  by  the  Navy 
Department,  April  30,  1910. 

I.  The  dry  pigment  must  contain  at  least  5  per  cent.,  by  weight,  of  the 
finest  red  lead,  at  least  40  per  cent,  of  zinc  oxide,  and  at  least  20  per  cent., 
by  weight,  of  iron  oxide  and  must  not  contain  more  than  5  per  cent.,  by 
weight,  of  lime  in  any  form. 

S.  The  pigment  must  be  of  the  best  quality  finely  ground  in  absolutely 
pure,  well-settled  and  perfectly  clear  raw  linseed  oil  of  the  best  quality 
only  to  a  medium  stiff  paste,  which  will  break  up  readily  in  thinning,  and 
must  be  free  from  grit,  adulterants,  and  all  impurities. 

3.  The  color,  shade,  tone,  fineness  and  coloring  power,  determined  by 
assaying  with  French  vv^hite  zinc  in  oil,  must  be  equal  to  the  standard 
sample  which  may  be  seen  at  the  general  storekeepers'  offices  in  the 
various  navy  yards. 

4.  Unless  otherwise  specified,  the  material  is  to  be  delivered  in  fric- 
tion-top cans  of  the  required  size  or  sizes,  properly  labeled  with  the  name 
of  the  material,  the  capacity  of  the  can,  and  4he  name  of  the  manufac- 
turer. Cans  of  5  pounds  capacity  and  over  must  be  provided  with  bails ; 
net  weight  to  be  delivered. 

Specifications  for  Aluminum  Paint,  Issued  by  the  Navy 
Department,  Aug^ist  2,  1915. 

To  be  of  the  best  quality  and  manufacture  and  consist  exclusively  of 
not  less  than  18  per  cent.,  by  weight;  of  finely  powdered  pure  aluminum 
in  accordance  with  Navy  Department  Specifications  for  Powdered  Alumi- 
num in  a  vehicle  containing  by  volume  25  to  30  per  cent,  of  pure  hard 
varnish  resins,  4  to  5  per  cent,  of  pure  raw  linseed  oil,  65  to  70  per  cent, 
of  pure  gum  spirits  of  turpentine  conforming  to  the  latest  issue  of  Navy 
Department  Specifications  for  Turpentine,  lead-manganese  driers,  and  be 
free  from  all  adulterants  or  other  foreign  materials. 

34 


530  I^NGINEERING   CHEMISTRY 

The  paint  shall  not  flash  below  105°  F.  (open  tester)  and,  when  applied 
to  a  steel  plate  alongside  of  a  standard  sample,  shall  be  equal  to  the 
standard  in  color,  brightness,  body,  finish,  covering  properties,  elasticity, 
and  durability.  When  exposed  to  the  action  of  oil,  steam,  and  salt  water, 
to  be  equal  to  the  standard  in  all  respects. 

Heat-resisting  qualities :  Iron  articles  dipped  in  the  paint  shall  be 
subjected  to  a  dull  red  heat.  The  color  should  not  change  greatly,  and 
there  should  be  practically  no  blistering  or  cracking  off  of  the  paint. 
Iron  articles  treated  as  above  should  show  but  slight  cracking  off  of  the 
paint  when  plunged  while  red  hot  into  water. 

Portions  of  the  standard  sample  referred  to  in  paragraph  2  may  be 
obtained  upon  application  to  the  construction  officer's  office  at  the  various 
navy  yards. 

Fire-proof  Paints,  Silicate  Paints,  Asbestos  Paints,  etc. 

The  principle  of  action  of  these  paints  is  not  to  render  v^ood- 
work  or  similar  material  fire-proof,  but  to  retard  combustion. 

Wood  treated  with  a  solution  of  zinc  chloride,  or  w^ith  a  solution 
of  sodium  silicate,  can  be  rendered  nearly  non-inflammable,  and 
after  such  treatment  and  drying,  paint  can  be  applied. 

Instead  of  using  the  ordinary  paints  for  this  purpose,  various 
compounds  are  incorporated  in  the  paint  itself  to  render  the  latter 
non-inflammable.  Thus  the  preparation  of  Prof  Abel  J.  Martin, 
of  Paris,  is  as  follows :  Boracic  acid,  borax,  soluble  cream  of 
tartar,  ammonium  sulphate,  potassium  oxalate,  and  glycerine 
mixed  with  glue  and  incorporated  with  a  paint.  It  is  the  result 
obtained  after  many  experiments  in  response  to  a  prize  of  1,000 
francs,  offered  by  the  Society  for  the  Advancement  of  National 
Industry  in  France.  A  committee  consisting  of  Professors  Du- 
mas, Palaird,  and  Troost,  after  testing  the  materials,  consisting  of 
painted  woods  and  various  fabrics,  for  7  months,  reported  in 
favor  of  this  preparation.  The  municipality  of  Paris  made  its 
use  obligatory  in  all  of  the  theatres  there  and  it  has  stood  the  test 
of  the  last  8  years. 

Blue  Pigments. — Ultramarine  being  a  silicate,  can  be  analyzed 
by  the  scheme  on  page  514. 


ENGINEE^RING   CHEMISTRY  53 1 

Composition  op  Ui^tramarine. 

Per  cent. 

Si02  49.68 

AI2O3    23.00 

S 923 

S03   2.46 

NaiO 12.50 

H.O 3-13 

Total   100.00 

Prussian  Blue.^ 

Under  the  name  Prussian  blue  are  included  all  ferrocyanid 
blues  such  as  Antwerp  blue,  Chinese  blue,  Turnbull's  blue,  etc. 
These  blues  are  all  ferric  ferrocyanides,  ferrous  ferricyanides,  or 
double  iron  potassium  salts  of  hydro- ferrocyanic  or  hydro-ferri- 
cyanic  acids.  The  analysis  of  these  blues,  as  is  generally  the  case 
with  pigments,  does  not  necessarily  give  results  which  can  be 
used  to  grade  samples,  the  strength  and  color  tests  being  most 
important.  Most  text  books  say  that  Prussian  blue  is  ferric 
ferrocyanide,  Fe4[Fe(CN)6]3,  but  this  substance  is  not  known 
commercially.  Commercial  Prussian  blue  is  a  mixture  of  Wil- 
liamson's blue,  KFe[Fe(CN)6],  with  other  iron-alkali  cyanids 
and  often  with  aluminum-iron  cyanids,  altogether  a  most  com- 
plex substance.^ 

Moisture. 

For  the  determination  of  moisture  dry  2  grams  for  2  hours 
at  100°  C.  Dry  blue  should  contain  less  than  7  per  cent,  of 
moisture. 

Insoi.uabi,e:  Impurities. 

Ignite  I  gram  in  a  porcelain  dish  iat  a  low  temperature. 
The  ignition  should  be  carefully  carried  out  at  a  temperature 
just  high  enough  to  decompose  the  last  trace  of  blue,  but 
not  high  enough  to  render  the  iron  insoluble,  in  hydrochloric 
acid.  Cool,  add  15  cc.  of  hydrochloric  acid,  digest  for  i 
hour  on  the  steam  bath  covered    with    a    watch    glass,    evapo- 

1  Percy  H.  Walker,  Bulletin  Chemistry,  109.  U.  S.  Dept.  Agriculture. 
•  Parry  and  Coste,  The  Analyst,  1906,  21,  225-230. 


532 


e:ngini:kring  chemistry 


rate  to  a  syrup,  add  water,  boil,  filter  from  the  insoluble,  wash, 
ignite,  weigh,  and  determine  the  nature  of  the  insoluble,  probably 
barium  sulphate.  In  pure  Prussian  blue  solution  should  be 
complete. 

ToTAi,  Iron. 

Decompose  as  in  the  foregoing  determination,  reduce,  and  de- 
termine the  iron  in  the  ordinary  way.  There  should  not  be  less 
than  30  per  cent,  calculated  on  the  dry  pigment. 

ToTAi.  Nitrogen. 
Determine  on  a  i-gram  sample  by  the  official  Gunning  method, 
digesting  for  3  hours. ^  The  percentage  of  Prussian  blue  may 
be  obtained  with  sufficient  accuracy  for  commercial  purposes 
by  multiplying  the  percentage  of  nitrogen  by  4.4  and  by  mul- 
tiplying the  percentage  of  iron  by  3.03.  Eight  samples  of  pure 
Prussian  blue  examined  by  Parry  and  Coste  gave  the  mean  re- 
sults from  which  these  factors  are  calculated.  The  following 
table  shows  the  accuracy  with  which  these  factors  give  the  per- 
centage of  Prussian  blue  in  the  eight  samples : 


Parry  and  Coste's  Determination  oe  the  Percentage  01 
Beue  in  the  Dry  Matter  oe  Eight  Samples. 

'  Prussian 

Factors 

No.  I 

No.   2 

No.   3 

No.  4 

No.   5 

No.  6 

No.  7 

No.  8 

Nitrogen  X  4-4 

Iron  ^  1  ox 

94.69 
94-63 

100.93 
101.02 

107.58 
109.71 

94.91 
97.11 

98.95 
94.84 

99.83 
98.99 

100.80 
102.47 

102.52 
100  26 

Other  Ddtejrminations. 
It  is  seldom  worth  while  to  make  any  further  determinations. 
If  desired,  however,  the  iron  and  aluminum  may  be  precipitated 
as  hydrates  by  ammonium  hydroxide  and  weighed  together  as 
oxides,  and  the  aluminum  obtained  by  difference  after  determin- 
ing the  iron  volumetrically  and  calculating  to  ferric  oxide.  The 
filtrate  from  the  iron  oxides  and  alumina  precipitate  may  be  made 
up  to  a  definite  volume  and  one  aliquot  taken  for  the  determin- 
ation of  sulphate  and  another  evaporated  with  sulphuric  acid, 
ignited,  and  weighed.     Determine  whether  the  alkali  is  sodium 

1  U.  S.  Dept.  Agr.,  Bureau  of  Chemistry,  Bulletin  No.  107,  p.  7. 


DNGINKEJRING   CHEMISTRY  533 

or  potassium  and  subtract  the  alkali  metal  corresponding  to 
the  sulphate  (SO4)  found.  The  remainder  is  double  alkali  iron 
ferrocyanide.  Well-washed  blues  should  be  neutral  in  reaction. 
The  red  shade  may  be  due  to  organic  red.  Test  the  solubility 
in  alcohol,  etc. 

Vermilion. 

True  vermilion,  or,  as  it  is  generally  called,  English  vermilion, 
is  sulphide  of  mercury.  On  account  of  its  cost  it  is  rarely  used 
in  paints  and  is  liable  to  gross  adulteration.  It  should  show  no 
bleeding  on  boiling  with  alcohol  and  water  and  no  free  sulphur 
by  extraction  with  CSg-  A  small  quantity  mixed  with  5  or  6 
times  its  weight  of  dry  sodium  carbonate  and  heated  in  a  glass 
tube  should  show  globules  of  mercury  on  the  cooler  portion  of 
the  tube. 

The  best  test  for  the  purity  is  the  ash,  which  should  not  be- 
more  than  J^  of  I  per  cent.  Make  the  determination  in  a 
porcelain  dish  or  crucible,  using  2  grams  of  the  sample.  If  it 
be  desired  to  determine  the  amount  of  mercury,  proceed  as  fol- 
lows :  Place  in  the  closed  end  of  a  combustion  tube  45  centimeters 
long  and  10  to  15  millimeters  in  diameter,  a  layer  of  25  to  50 
millimeters  of  roughly  pulverized  magnesite,  then  a  mixture  of 
10  to  15  grams  of  the  vermilion  with  four  or  five  times  its  weight 
of  lime,  followed  by  5  centimeters  of  lime,  and  plug  the  tube  with 
asbestos.  Draw  out  the  end  of  the  tube  and  bend  it  over  at  an 
angle  of  about  60°.  Tap  the  tube  so  as  to  make  a  channel  along 
the  top,  and  place  it  in  a  combustion  furnace  with  the  bent  neck 
down,  resting  with  its  end  a  little  below  some  water  in  a  small  flask 
or  beaker.  Heat  first  the  lime  layer,  and  carry  the  heat  back  to 
the  mixture  of  lime  and  pigment.  When  all  the  mercury  has  been 
driven  off,  heat  the  magnesite,  and  the  evolved  carbon  dioxide  will 
drive  out  the  last  of  the  mercury  vapors.  Collect  the  mercury  in 
a  globule,  wash,  dry,  and  weigh. 

Genuine  vermilion  is  at  the  present  time  little  used  in  paints. 
Organic  lakes  are  used  for  most  of  the  brilliant  red,  scarlet,  and 
vermilion  shades.  These  organic  coloring  matters  are  sometimes 
precipitated  on  red  lead,  orange  mineral,  or  zinc  oxide;  but  as  a 


534 


ENGINEERING   CHEMISTRY 


usual  thing  the  base  is  barytes,  whiting,  or  China  clay.  Parani- 
traniline  red,  a  compound  of  diazotized  paranitraniline  and  beta- 
naphthol  is  largely  employed;  but  a  number  of  colors  may  be 
used.  To  test  for  red  colors  in  such  a  lake  the  following  method 
from  Hall  may  be  of  value,  though  other  colors  may  be  employed, 
which  makes  the  table  of  only  limited  use. 

Determination  of  Red  Coi^ors  in  Organic  Lake 


Reagent 


Sulphuric 
acid,  cone 


Hydro- 

chloric 

acid,  cone. 


Sodium 

hydroxide. 

cone.  sol. 


Alcohol 


Sodium 

hydroxide, 

cone,  and 

alcohol 


Source  of  color 


Dark  brown  with 
reddi.sh  under- 
tone becoming 
light  yellow  on 
diluting. 


Color   becomes 
muddy." 


Dark  reddish 
brown;  little 
change  on  di- 
luting. 

Insoluble  .... 


Purplish;  dark 
brown  on  di- 
luting. 


Eosine 


Changes  to  yel- 
low; fluores- 
cent solution 
with  excess  of 
sodium  hy- 
droxide. 

Changes  to  yel- 
low; reddish 
fluorescent  so- 
lution with  ex- 
cess of  sodium 
hydroxide. 

Ivittle  change; 
fluorescent  .so- 
lution on  dilut- 
ing. 

Reddish  fluores- 
cent solution. 


Para-nitraniline    ai?is\dhie      Scarlet  (2R) 


Purple  color  re 
turning  on  di- 
luting. 


Color  slightly 
darkened; 
lighter  on  di- 
luting. 


Color  changed  to 
brownish  red; 
light  red  on  di- 
luting. 

Slight  yellowish 
orange  solu 
tion. 

Purple;  color  re 
turning  on  di- 
luting. 


Purple;  red 
on  dilut 
ing. 


Dark  pur 
plish  red 
lighter  on 
diluting 


I^ittle 
change 


Ivittle 
chslnge. 


Darkened; 
lighter  on  di- 
luting. 


Darkened, 
lighter  on  di- 
luting 


Reddish  solu- 
tion on  dilut 
ing. 


Slight   reddish 
solution. 


Color  darker, 
reddish  solu- 
tion on  dilut- 
ing. 


It  is  well  also  to  try  the  action  of  reducing  and  oxidizing  agents 
such  as  stannous  chloride,  ferric  chloride,  etc.  (See  also  Schultz 
and  Julius,  A  Systematic  Survey  of  the  Organic  Coloring  Mat- 
ters.) 

Paranitranilin  red  is  soluble  m  chloroform.  It  is  also  well  to 
try  the  solvent  action  on  different  reds  of  sodium  carbonate,  etc. 
The  amount  of  organic  pigment  present  in  such  reds  is  generally 
very  small,  and  when  it  can  not  be  determined  by  ignition  owing 
to  the  presence  of  lead,  zinc,  or  carbonate,  it  is  best  determined 
by  difference.     (Percy  H.  Walker.) 


DNGINEJERING   CHEMISTRY  535 

Extraction  of  the  Vehicle  in  Mixed  Paints. 

Weigh  from  15  to  35  grams  of  the  thoroughly  mixed  pigment 
in  a  tall,  narrow  Erlenmeyer  flask  of  300  cc.  capacity.  Add  150 
cc.  of  gasolene,  stopper  with  a  cork,  and  shake  for  10  minutes 
with  a  shaking  machine  so  constructed  that  the  liquid  is  not 
brought  in  contact  with  the  stopper;  allow  to  stand  until  the 
pigment  has  settled,  and  decant  the  liquid  into  a  beaker;  some 
pigment  will  frequently  go  over  with  the  gasolene,  so  it  is  well 
to  allow  this  to  settle  and  decant  into  a  second  beaker.  Repeat 
the  treatment  with  gasolene;  after  the  first  treatment  settling  is 
generally  much  more  rapid.  Decant  the  gasolene  as  completely  as 
possible  the  second  time.  Then  add  150  cc.  of  benzol  (CgHe), 
shake  and  allow  to  settle.  Decant  the  benzol  and  treat  in  same 
way  with  150  cc.  of  ether.  This  method  of  extraction  is  often 
more  satisfactory  than  any  method  using  a  continuous  extraction 
apparatus ;  for  frequently  the  pigments  can  not  be  held  by  extrac- 
tion thimbles.  This  method  of  treatment  will  generally  give  an  al- 
most complete  separation  of  the  vehicle;  but  in  some  enamel 
paints  it  is  well  to  follow  the  gasolene  treatment  by  a  treatment 
with  turpentine,  and  then  remove  the  turpentine  with  gasolene,  be- 
fore treating  with  benzol  and  ether.  No  system  of  extraction 
will  remove  absolutely  all  the  vehicle,  the  insoluble  portion  being 
probably  metallic  soaps  or  linoxyn. 

After  removing  all  of  the  soluble  vehicle,  dry  the  pigment,  first 
at  a  low  temperature  in  a  gentle  current  of  air,  and  then  at 
105°  C,  weigh,  and  from  the  loss  in  weight  calculate  the  per- 
centage of  vehicle  and  pigment;  then  from  the  total  weight  of 
mixed  paint  and  the  weight  of  clear  vehicle  drawn  off  calculate 
the  percentage  of  vehicle  and  pigment  in  the  original  paint. 

Analysis  of  the  Vehicle  from  Paint. 

Weigh  50  grams  of  the  vehicle  into  a  500  cc.  flask,  connect 
with  a  spray  trap  and  a  vertical  condenser,  and  pass  through  it 
a  current  of  steam,  first  heating  the  flask  in  an  oil  bath  at 
icx)°  C. ;  with  the  steam  still  passing  through,  raise  the  tempera- 
ture of  the  bath  to  130°.    Catch  the  distillate  in  a  small  weighed 


536  ENGINEERING    CHEMISTRY 

separatory  funnel ;  continue  distillation  until  the  funnel  contains 
150  cc.  of  water.  Let  the  distillate  stand  until  separated  into  two 
layers,  then  draw  off  the  water,  and  weigh  the  light  oils.  Ex- 
amine as  under  turpentine,  page  538. 

A  slight  error  is  caused  by  the  solubility  of  turpentine  in  water ; 
this  amounts  to  about  0.3  to  0.4  cc.  for  each  100  cc.  of  water. 
Cut  off  the  steam,  remove  the  trap,  and  draw  air  through  the 
flask  for  about  15  minutes,  keeping  the  oil  bath  at  130°  C.  The 
residue  is  now  free  from  water  and  can  be  examined  according 
to  the  following  procedure  for  the  residue  from  dry  distillation : 

When  sufficient  vehicle  is  available  it  is  well  to  take  another 
portion  and  distill,  without  steam,  placing  the  flask  in  an  air 
bath.  Note  the  temperature  of  the  bath  at  which  distillation  takes 
place,  and  continue  the  distillation  at  a  temperature  of  185°  C. 
in  the  air  bath.  This  method  gives  somewhat  lower  results  on 
volatile  oils  than  the  first  method,  but  the  distillate  can  be  tested 
for  water-soluble  volatile  liquids  which  would  be  lost  by  the 
steam  distillation.  Unsaponifiable  matter  should  be  determined 
in  this  residue,  or  in  some  of  the  original  vehicle. 

The  residue  is  frequently  too  pasty  for  the  determination  of 
the  specific  gravity,  which  should  be  made  on  the  original  vehicle. 
Determine  the  acid  number  of  the  residue  of  the  original  vehicle. 
Determine  the  percentage  and  the  character  of  the  ash  either 
from  the  residue  or  the  original  vehicle.  The  iodine  number 
is  sometimes  a  useful  index;  but  the  constants  of  linseed  oil 
which  has  been  mixed  with  pigments,  especially  lead  compounds, 
may  be  so  much  altered  that  an  iodine  number  as  low  as  100  can 
not  be  taken  as  any  proof  of  the  presence  of  other  fatty  oils. 

Test  for  resin  may  be  made  by  dissolving  in  carbon  disulphide 
and  adding  a  solution  of  stannic  bromide  or  chloride  in  carbon  di- 
sulphide. Use  a  white  porcelain  dish.  If  no  water  is  present  in 
either  solution  the  presence  of  resin  is  shown  by  the  appearance 
of  a  violet  color.  This  test  is  not  as  delicate  as  the  Liebermann- 
Storch  test  described  under  linseed  oil. 

When  much  lead  is  present  it  may  be  lost  in  ashing,  and  for 
a  correct  determination  of  metals  the  following  method  is  best: 


e:ngine:e:ring  chemistry  537 

Place  25  grams  of  the  vehicle  in  a  500  cc.  separatory  funnel, 
dilute  with  25  cc.  of  a  mixture  of  equal  parts  of  gasolene  and 
turpentine,  add  50  cc.  of  nitric  acid  (i  :  i),  and  let  stand  i  hour, 
shaking  every  10  minutes.  Then  immerse  the  funnel  in  hot  water, 
loosen  the  stopper  and  shake  gently.  This  drives  off  nearly  all 
the  gasolene.  Remove  from  the  hot  water,  let  it  separate,  draw 
off  the  lower  layer,  and  wash  the  upper  oily  layer  four  or  five 
times  with  warm  water.  Add  the  washings  to  the  main  acid  por- 
tion and  determine  the  metals  in  the  ordinary  manner.  If  the 
paint  is  enamel  paint,  treat  the  vehicle  as  a  varnish. 


VARNISH. 


The  methods  of  analysis  for  varnish  are  far  from  satisfactory. 
The  following  method,  slightly  modified,  is  one  devised  by  S.  S. 
Voorhees,  and  while  not  absolutely  satisfactory,  is  probably  the 
best  available : 

iNSoiyUBivE  Gums. 
Weigh  2  grams  of  the  varnish  into  a  weighed  150  cc.  Erlen- 
meyer  flask,  add  2  cc.  of  chloroform,  and  then  100  cc.  of  88°  B. 
gasolene;  add  the  gasolene  gradually,  shaking  constantly  so  as  to 
avoid  any  precipitation,  until  15  cc.  are  added.  Allow  to  stand 
over  night  in  a  cool  place.  The  gums  will  adhere  to  the  bottom 
and  side  of  the  Erlenmeyer  flask;  decant  into  a  weighed  beaker 
and  wash  with  a  little  88°  gasolene.  Dry  for  2  hours  at  105°  C. 
and  weigh  as  insoluble  gums. 

Soi.uBi,E  Gums  and  Linoxyn. 
Evaporate  the  gasolene  extract  and  dry  the  residue  for  168 
hours  at  100°  to  105°  C,  or  to  constant  weight,  and  weigh.  This 
treatment  should  convert  all  linseed  oil  into  linoxyn.  Add  15  cc. 
of  chloroform  and  digest  over  night  to  dissolve  the  gums  but 
not  the  linoxyn.  Filter  through  a  wad  of  absorbent  cotton  into 
a  weighed  beaker,  evaporate  the  chloroform,  dry  for  2  hours  at 
105°,  and  weigh  as  soluble  gums.  Einoxyn  is  obtained  by  dif- 
ference from  the  first  weight. 


538  dnginbering  chemistry 

Acid  Vai,ue. 
Determine  the  acid  value  in  the  usual  way  on  10  grams  of  the 
varnish.    After  getting  the  acid  value,  decant  the  alcohol,  evapo- 
rate, and  apply  the  Liebermann-Storch  test  for  resin. 

Ash. 
Determine  the  ash  on  10  grams  (in  a  porcelain  dish).     Deter- 
mine the  reaction  of  ash  with  litmus  paper;  if  alkaline,  test  for 
lime.     It  is  sometimes  well  to  determine  lime,  a  large  amount  of 
which  indicates  resin. 

Misce;i.i.ane:ous. 

Volatile  oils  and  metals  are  determined  as  in  the  analysis  of 
the  vehicle  under  mixed  paints. 

It  is  not  possible  from  such  an  examination  as  has  been  de- 
scribed to  decide  on  the  va-lue  of  a  varnish  for  any  particular  pur- 
pose. An  examination  of  the  varnish  film  should  always  be  made. 
The  film  is  best  made  by  flowing  the  varnish  on  glass,  and  films 
should  be  dried  in  both  a  horizontal  and  a  vertical  position  at  a 
uniform  temperature,  38°  C.  Note  the  time  of  setting,  the  ap- 
pearance, the  hardness  and  toughness  of  film. 


TURPENTINE. 


Directions  for  the;  Anai^ysis  o^  Turpentine. 

Appearance. — On  receipt  of  samples,  note  and  record  whether 
the  samples  are  free  from  dirt,  suspended  matter  and  water.  If 
the  samples  contain  water,  filter  through  a  dry  filter  paper  into 
a  clean  dry  bottle. 

Color. — Into  a  200-millimeter  colorimeter  tube  graduated  into 
millimeters,  place  50  cc.  of  the  turpentine  to  be  examined ;  on  the 
tube  place  a  No.  2  Lovibond  yellow  glass ;  over  a  second  200  milli- 
meter tube,  place  a  No.  i  Lovibond  yellow  glass;  add  to  the 
second  tube  enough  of  the  sample  of  turpentine  to  match  the 
color  in  the  first  tube,  and  record  its  reading  in  millimeters. 

Specific  Gravity. — Determine  the  specific  gravity  by  any  suit- 


DNGIN^E^RING   CHEMISTRY  539 

able  accurate  method  and  report  as  specific  gravity  at 
15°. 5/15°. 5  C.    State  the  method  used. 

Refractive  Index. — Determine  with  a  direct  reading  refrac- 
tometer  at  15*^.5  C. 

Distillation  Test. —  (i)  Place  200  cc.  of  the  sample  into  a 
300-cc.  flask,  8  centimeters  in  diameter,  with  a  side  tube  8  centi- 
meters from  the  main  bulb,  and  the  neck  extending  8  centimeters 
above  the  side  tube.  The  neck  is  2  centimeters  in  diameter  and 
the  side  tube  5  millimeters.  This  flask  should  be  fitted  with  a 
thermometer  (reading  from  145  to  200°  C.)  immersed  in  the 
vapor.  The  mercury  bulb  should  be  opposite  the  side  tube  of  the 
flask  and  the  reading  175°  C.  should  be  below  the  cork.  The  dis- 
tillation should  be  so  conducted  that  there  shall  pass  over  about 
2  drops  of  the  distillate  per  second. 

(2)  Place  100  cc.  of  the  sample  into  an  ordinary  Engler  flask. 
Have  thermometer  totally  immersed  in  the  vapor  as  directed  in 
the  specifications  in  test  No.  i. 

(3)  Place  100  cc.  of  the  sample  in  an  ordinary  Engler  flask 
(see  test  No.  2)  and  use  an  ordinary  long-stem  thermometer. 
Report  emergent  reading  and  approximate  length  of  the  exposed 
mercury  column  and  its  approximate  temperature. 

In  all  three  methods  of  distillation  note  and  report  the  initial 
boiling  point.  Note  temperature  at  each  10  cc.  of  distillate  and 
note  volume  of  distillate  at  160,  165,  170  and  175°  C.  If  possible, 
note  and  report  barometric  pressure  at  time  of  making  distilla- 
tion. 

Evaporation  Test. — Ten  cubic  centimeters  of  the  sample  are 
placed  in  a  glass  crystallizing  dish,  2^  inches  in  diameter  and 
I  ^  inches  high,  and  evaporated  on  an  open  steam  bath  with  a  full 
head  of  steam  for  2  hours.  Cool,  weigh,  and  report  weight  of 
residue  in  grams. 

Polymerisation. — (i)  Add  slowly  5  cc.  of  the  turpentine  to 
25  cc.  of  sulphuric  acid  (specific  gravity  1.84)  contained  in  an  or- 
dinary, graduated,  narrow-necked  Babcock  flask.  Shake  the 
flask  with  a  rotary  motion  to  insure  gradual  mixing.  Cool  if 
necessary  in  ice  water,  not  permitting  the  temperature  to  rise 


540  DNGINKERING   CHEMISTRY 

above  60  to  65°  C.  Agitate  thoroughly  and  maintain  at  about 
65°  C.  with  frequent  agitations  for  i  hour.  Cool,  fill  the  flask 
with  H2SO4,  bringing  the  unpolymerized  oil  into  the.  graduated 
neck.  Allow  to  stand  i  hour.  Read  off  unpolymerized  content; 
note  and  report  its  consistency  and  color,  and  determine  its  re- 
fractive index  at  15°. 5  C. 

(2)^  Repeat  test  No.  i  but  use  sulphuric  acid  that  is  38  N  and 
let  flasks  stand  24  hours  before  reading  the  amount  of  unpoly- 
merized residue,  or  else  centrifuge  5  minutes. 

Hydrochloric  Acid  Test. — Shake  10  cc.  of  the  turpentine  with 
10  cc.  of  concentrated  hydrochloric  acid  (specific  gravity,  1.19). 
Note  whether  after  3  minutes  standing  a  decided  red  color 
develops.  (Test  for  the  presence  of  furfural  or  heavy  or  resinous 
oils.) 

Flash  Point. —  (i)  Support  a  100  cc.  nickel  crucible,  such  as  is 
used  in  determining  the  flash  point  of  linseed  oil,  in  a  vessel  of 
water  at  15  to  20°  C. ;  the  water  should  cover  about  two-thirds  of 
the  crucible.  Fill  the  crucible  to  within  about  2  centimeters  of 
the  top  with  turpentine,  insert  a  thermometer,  and  heat  the  water 
bath  slowly  so  that  the  temperature  of  the  turpentine  rises  1°  C. 
per  minute.  Begin  at  37°  C.  and  test  for  the  flash  at  each  rise  of 
o°.5  C.     Report  temperature  at  which  the  turpentine  flashes. 

(2)  Determine  the  flash  point  using  the  Tagliabue  open  cup. 
Begin  testing  at  30°  C.  and  test  at  each  degree  Centigrade  above 
that  till  the  sample  flashes.  The  temperature  of  the  turpentine 
should  not  rise  more  rapidly  than  1°  C.  per  minute. 

(3)  Use  a  closed  tester  such  as  the  Pensky-Martin  tester,  the 
Abel  cup,  etc.,  following  the  directions  for  the  instrument. 

Specifications  for  Spirits  of  Turpentine,  B.  &  0.  R.  R.  Co. 

I.  The  material  desired  is  the  properly  prepared  distillate  of  pine,  or 
pine  pitch,  unmixed  with  any  other  substance. 

a.  It  must  be  water  white  or  prime  white  in  color. 
h.  Its  gravity  must  be  between  0.862  and  0.872°  F. 
c.  It  must  boil  between  310  and  320°  F.,  and  at  least  95  per  cent, 
must  distill  over  below  338°  F. 

i  Donk's  Method  ;  Bulletin  No.  /jj  or  Circular  No.  15,  Bureau  of  Chemistry. 


ENGINEERING   CHEMISTRY  54I 

d.  Upon  evaporation  at  212°   F.,  the  residue  must  not  exceed  2 

per  cent. 

e.  When  6  cc.  of  the  material  are  thoroughly  mixed  with  24  cc. 

of   concentrated   sulphuric    acid   in   a   graduated    tube,    kept 
cool  while  mixing  and  the  mixture  allowed  to  stand  for  ^ 
hour,  not  more  than  6  per    cent,    must    separate,  as  a  clear 
layer. 
/.  Weight  to  be  calculated  at  7  pounds  per  gallon. 

2.  Material  failing  to  meet  the  above  tests  or  found  by  other  standard 
tests  to  be  impure  will  be  rejected. 

3.  All  rejected  material  will  be  returned,  the  shipper  paying  freight 
both  ways. 

Determination  of  Resin  in  Shellac. 

Standard  Method  i^or  the  Determination  of 
Resin  in  Shei.i.ac. 
The  solutions  required  are  one  of  iodine  monochloride  contain- 
ing 13  grams  of  iodine  per  liter,  in  glacial  acetic  acid  that  has  a 
melting  point  of  14.7  to  15°  C.  and  is  free  from  reducing  impuri- 
ties; and  another  of  sodium  thiosulphate,  made  by  dissolving 
24.83  grams  of  the  pure  salt  in  a  liter  of  water.  In  addition  to 
these  solutions  there  is  required  a  quantity  of  acetic  acid  of  the 
same  strength  as  that  used  for  making  the  solution  of  iodine 
monochloride.  Pure  chloroform  and  starch  are  also  necessary. 
The  preparation  of  the  iodine  monochloride  solution  presents  no 
great  difficulty,  but  it  must  be  done  with  care  and  accuracy  in 
order  to  obtain  satisfactory  results.  There  must  be  in  the  solu- 
tion no  sensible  excess  either  of  iodine  or  more  particularly  of 
chlorine,  over  that  required  to  form  the  monochloride.  This 
condition  is  most  satisfactorily  attained  by  dissolving  in  the  whole 
of  the  acetic  acid  to  be  used  the  requisite  quantity  of  iodine,  using 
a  gentle  heat  to  assist  the  solution,  if  it  is  found  necessary.  Set 
aside  a  small  portion  of  this  solution,  while  pure,  and  pass  dry 
chlorine  into  the  remainder  until  the  halogen  content  of  the  whole 
solution  is  doubled.  Ordinarily  it  will  be  found  that  by  passing 
the  chlorine  into  the  main  part  of  the  solution  until  the  character- 
istic color  of  free  iodine  has  just  been  discharged,  there  will  be 
a  slight  excess  of  chlorine,  which  is  corrected  by  the  addition  of 


542  ENGINEERING   CHEMISTRY 

the  requisite  amount  of  unchlorinated  portion  until  all  free  chlor- 
ine has  been  destroyed.  A  slight  excess  of  iodine  does  little  or 
no  harm,  but  excess  of  chlorine  must  be  avoided. 

Introduce  0.2  gram  of  ground  shellac  into  a  250  cc.  dry  bottle 
of  clear  glass  with  a  ground  glass  stopper,  add  20  cc.  of  glacial 
acetic  acid  (melting  point  14.7  to  15°  C.)  and  warm  the  mixture 
gently  until  solution  is  complete  (except  for  the  wax).  A  pure 
shellac  is  not  easily  soluble;  solution  is  quicker  according 
to  the  proportion  of  resin  present.  Ten  cubic  centimeters  of 
chloroform  are  added  and  the  solution  is  cooled  to  21  to  24°  C. 
The  temperature  should  be  held  well  within  these  limits  during  the 
test.  Twenty  cubic  centimeters  of  Wijs  solution  are  added  from 
a  pipette,  having  a  rather  small  delivery  aperture.  The  bottle  is 
closed  and  placed  in  a  dark  place,  and  the  time  noted.  It  is  con- 
venient to  keep  the  bottles  during  the  test  partly  immersed  in 
water  which  should  be  kept  as  nearly  as  possible  between  22  and 

23°  c. 

Pure  shellac  will  scarcely  alter  the  color  of  the  Wijs  solution. 
If  in  small  amount,  resin  will  produce  a  slowly  appearing  red- 
brown  color.  In  large  amount,  resin  causes  an  immediate  color- 
ation, increasing  in  intensity  as  time  passes.  After  i  hour  10  cc. 
of  10  per  cent,  potassium  iodide  water  solution  are  added.  The 
solution  is  immediately  titrated,  with  the  sodium  thiosulphate 
solution ;  25  or  30  cc.  may  be  run  in  immediately,  unless  the  shellac 
is  very  impure,  and  the  remainder  gradually,  with  vigorous  shak- 
ing. Just  before  the  end,  a  little  starch  solution  is  added.  The 
end  point  is  sharp,  as  the  reaction  products  of  shellac  remain 
dissolved  in  the  chloroform;  any  color  returning  after  ^  minute 
or  so  is  disregarded. 

A  blank  determination  should  be  run  with  20  cc.  Wijs  solu- 
tion, 20  cc.  of  acetic  acid,  10  cc.  of  chloroform,  and  10  cc.  of 
10  per  cent,  potassium  iodide  solution.  The  blank  is  necessary 
on  account  of  the  well  known  effect  of  temperature  changes  on 
the  volume,  and  possible  loss  of  strength  of  the  Wijs  solution. 

In  the  case  of  grossly  adulterated  samples,  or  in  the  testing  of 
pure  resin,  it  is  necessary  to  use,  instead  of  0.2  gram  of  material, 
a  smaller  amount,  say  0.15  gram  or  even  o.i  gram,  in  order  that 


ENGINEERING    CHEMISTRY  543 

the  excess  of  iodine  monochloride  may  not  be  too  greatly  reduced, 
since  the  excess  of  halogen  is  one  of  the  factors  in  determining 
the  amount  of  absorption.  It  is  safe  to  say  that  in  case  less  than 
25  cc.  of  the  thiosulphate  solution  are  required,  another  test 
should  be  made,  using  a  smaller  amount  of  the  shellac  to  be 
tested. 

In  weighing  shellac,  some  difficulty  is  at  times  experienced  on 
account  of  its  electrical  properties.  In  very  dry  weather  it  may 
be  found  that  the  necessary  handling  to  prepare  it  for  weighing 
has  electrified  it,  and  that  it  may  be  necessary  to  leave  it  on  the 
balance  pan  at  rest  for  a  few  minutes  before  taking  the  final 
weight. 

No  pure  shellacs  show  a  higher  iodine  absorption  than  i8. 
As  shellac  is  relatively  a  high-priced  material  and  as  the  variation 
between  its  highest  and  lowest  figure  is  not  great,  the  sub-com- 
mittee believes  that  i8  should  be  taken  as  the  standard  figure  for 
shellac,  determined  by  the  method  above  described. 

As  it  is  an  accepted  principle  that  a  standard  method  should 
be  so  devised  that  its  inaccuracies  shall  work  in  the  direction  of 
favoring  the  seller  rather  than  of  condemning  too  severely  the 
article  sold,  the  sub-committee  approves  the  value  taken  by 
Doctor  Langmuir  for  the  iodine  number  of  resin,  namely,  228. 
The  results  of  using  in  this  method  the  value  18  as  the  iodine 
number  of  shellac  and  228  as  the  number  of  resin,  may  be  that 
a  slightly  lower  percentage  of  resin,  under  some  circumstances, 
will  be  found  than  that  which  is  actually  present. 

The  percentage  of  resin  is  determined  as  follows : 
Iodine  number  of  shellac   =     18 
Iodine  number  of  resin      =  228 
Iodine  number  of  mixture  =     X 

Percentage  of  resin  =100  --^ 

^  (228— iS)- 

References. 

"Painting  Defects,  Their  Causes  and  Prevention,"  by  Gustave  W.  Thomp- 
son, Jour.  Ind.  and  Eng.  Chem.,  Feb.,  1915. 

"The  Constitution  of  White  Lead,"  by  Edwin  Euston,  Jour.  Ind.  and  Eng. 
Chem.,  March,  1914. 


544  ENGINEERING   CHEMISTRY 

THE  CHEMICAL  AND  PHYSICAL  EXAMINATION  OF  PAPER. 

This  subject  may  be  conveniently  divided  into  eight  sections: 

1.  Determination  of  the  nature  of  the  fiber; 

2.  Microscopical  examination ; 

3.  Determination  of  free  acids; 

4.  Determination  of  the  nature  and  amount  of  the  sizing  used ; 

5.  Determination  of  the  amount  of  ash  and  its  analysis ; 

6.  Determination  of  the  weight  per  cubic  decimeter; 

7.  Determination  of  the  thickness  of  the  paper; 

8.  Determination  of  the  absolute  breaking  strength. 

1.   Determination  of  the  Nature  of  the  Fiber. 

The  introduction,  in  late  years,  of  the  various  kinds  of  wood 
fibers  in  the  manufacture  of  paper  has  rendered  the  chemical  ex- 
amination of  the  same  exceedingly  difficult. 

This  is  more  especially  so  where  the  wood  fiber  has  been  sub- 
jected to  chemical  treatment,  as  in  the  "sulphite  process"  or  the 
"soda  process,"  before  being  incorporated  in  the  paper. 

Nearly  all  of  the  chemical  reactions  for  the  recognition  of  the 
wood  fibres  in  paper  produce  certain  colors  with  the  various 
resins  in  the  wood  when  the  reagent  is  added.  While  the  fiber 
prepared  entirely  by  the  "mechanical"  process  can  be  indicated 
without  difficulty,  even  when  mixed  with  cotton  and  linen  in 
various  amounts,  the  conditions  are  greatly  altered  when  the 
wood  fiber  has  been  subjected  to  bleaching  and  chemical  treat- 
ment, since  the  latter  removes  much  of  the  resinous  matters  of 
the  wood  and  increases  the  difficulty  of  the  quantitative  exami- 
nation. 

The  chemical  reactions  of  the  fiber  produced  from  the  various 
woods  used  in  paper-making,  pine,  poplar,  and  spruce,  are  iden- 
tical, qualitatively,  with  the  following  reagents : 

1.  Hydrochloric  acid  and  phloroglucine  produce  a  red  color 

with  "mechanical"  wood  pulp ; 

2.  Analine  sulphate  produces  a  yellow  color ; 

3.  Naphthylamine  and  hydrochloric  acid  produce  an  orange 

yellow  color ; 

4.  Anthracene  hydrochlorate  produces  a  red  color ; 


ENGINEJERING   CHEMISTRY  545 

5.  Phenol  hydrochlorate  produces  a  bluish-green  color; 

6.  Concentrated  hydrochloric  acid  produces  a  violet  color; 

7.  Pyrrol  and  hydrochloric  acid  produce  a  purple-red  color; 

8.  Pyrogallic  acid  and  zinc  chloride    produce  a  dark    violet 

color ; 

9.  Nitric  and  sulphuric  acids  produce  a  red  color; 

10.  Hematoxylin  solution  produces  a  red  color; 

11.  Alcoholic  solution  of  cochineal  produces  a  blue-violet. 
Where  the  wood  pulp  is  composed  entirely  of  "mechanical" 

wood  fiber  the  above  reactions  are  very  marked  and  by  the  aid 
of  the  microscope,  the  varieties  of  wood  can  be  determined. 

Wood  pulp  produced  by  the  "soda"  or  by  the  "bisulphite" 
process  gives  a  much  weaker  reaction  with  the  chemical  reagents 
used  for  identification,  and  in  many  instances  where  the  pulp  has 
been  used  many  times  in  paper-making  will  give  no  color  reac- 
tions sufficient  for  recognition.  The  amount  of  "mechanical 
fiber"  in  a  mixture  of  "chemical  fiber,"  linen  fiber,  cotton  fiber 
and  "mechanical  fiber"  in  a  paper  can  be  determined  as  follows : 

The  sample  of  paper  is  first  boiled  in  water,  then  in  alcohol, 
and  afterwards  digested  with  ether.  After  drying,  a  solution  of 
gold  chloride  is  added. 

Linen,  cotton  and  "chemical"  wood  fiber  have  no  reducing 
action  upon  the  solution  of  gold;  but  the  mechanical  wood  fiber 
immediately  reduces  gold  from  the  solution,  this  action  being  due 
to  the  ligno-cellulose  remaining  in  the  mechanical  wood  fiber. 

One  hundred  grams  of  mechanical  wood  pulp,  under  above  con- 
ditions will  reduce  14,285  grams  of  gold.^ 

If  a  sample  of  paper  be  submitted  for  examination  as  to  the 
fibers  used  in  its  manufacture,  the  following  preliminary  work  is 
requisite:  The  rosin,  sizing,  filling,  etc.,  in  the  manufactured 
paper  must  first  be  removed.  Cut  the  paper  into  small  pieces, 
place  them  in  a  beaker  and  digest  with  a  solution  of  caustic  soda 
(i  part  caustic  soda  to  30  of  water),  at  a  moderate  heat  for  ten 
minutes.  Pour  off  the  liquid,  replace  with  double  the  amount 
of  distilled  water,  and  warm  ten  minutes;  pour  off  this  liquid, 
and  repeat  once.     Now  place  the  paper  in  a  solution  composed 

1  "Handbuch  der  technisch-chemische  Untersuchungen,"  (BoUey),  6  Auf.,  p.  1007. 
35 


546  ENGINEERING    CHEMISTRY 

of  I  part  hydrochloric  acid  and  15  parts  of  distilled  water  and 
digest  ten  minutes.  Wash  a  number  of  times  with  distilled  water, 
until  washings  are  no  longer  acid ;  then  dry. 

Suppose  the  sample  of  paper  so  treated  to  be  composed  of  a 
mixture  of  "mechanical"  chemical  wood  fiber,  linen  and  cotton 
— a  mixture  to  be  found  in  many  samples  of  good  quality  of 
writing  paper. 

A  sample  of  the  dried  paper  is  tested  with  solution  of  gold 
chloride.  If  no  reduction  of  gold  takes  place,  the  indications 
point  to  the  absence  of  mechanical  wood  fiber.  This,  however, 
is  not  absolute,  since,  if  the  paper  has  been  made  from  "cuttings," 
"old  paper  stock,"  etc.,  etc.,  the  mechanical  wood  pulp  might 
have  been  treated  quite  a  number  of  times  by  chemicals  in  the 
production  of  the  finer  quality  of  paper,  and  its  ligno-cellulose 
destroyed  or  modified  in  such  a  way  as  to  nullify  the  gold  test. 

Generally  speaking,  however,  the  reduction  of  the  gold  clo- 
ride  is  indicative  of  the  presence  of  mechanical  wood  fiber. ^ 

R.  Benedikt^  gives  a  method  for  the  determination  of  mechan- 
ical wood  fiber  in  paper,  dependent  upon  the  methyl  numbers  of 
lignin  contained  in  it.  This  process  has  been  tested  by  W. 
Herzberg^  with  the  result  that  preference  is  given  to  the  use  of 
gold  chloride  solution. 

If  the  amount  of  mechanical  wood  fiber  in  a  paper  amounts  to 
about  10  per  cent.,  Gottstein*  states  that  the  fibers  may  be 
counted  under  the  microscope,  after  the  fibers  have  first  been 
made  visible  by  a  treatment  with  an  alcoholic  phlorogiucinol  solu- 
tion and  hydrochloric  acid.  Fifteen  per  cent,  or  more  of  the 
mechanical  wood  fiber  in  the  mixture  renders  the  test  valueless. 
If  chemical  wood  fiber  be  present  in  a  paper  with  mechanical 
wood  fiber,  no  color  tests  for  the  former  are  positive  in  the  pres- 
ence of  the  latter,  since  the  mechanical  wood  pulps  possess  a 
greater  tinctorial  power. 

1  "Ueber  die  qualitative  Bestimmung  des  Holzschliffsim  Papier,"  von  Rich,  Godeflfroy 
und  Max  Conlon,  Mitteilungen  aus  dem  R.  K.  technologischen  Gewerbemuseum  in  Wien 
1888.  Mitteilungen  aus  dem  Koniglischen  technischen  Versuchsanstalten  zu  Berlin 
(1892)   p.  54. 

2  Chem.  Ztg.,  15,  201. 

3  Mitt.  Konig.  tech.  Versuchs  (1891),  44-50. 
<  Papier-Zeitung  (1884),  432. 


ENGINEERING   CHEMISTRY 


547 


Should  mechanical  wood  fiber  be  absent,  however,  a  solution 
of  resorcin  can  be  applied  to  a  properly  prepared  sample  of  the 
paper.  Chemical  wood  fiber  produces  a  violet  color,  whereas 
cotton  and  linen  are  without  action. 

A  solution  of  phenol  also  produces  a  violet  color  under  similar 
conditions. 


1 

\ 

i 

■'^s        \                 ... 

Fig.  93- 


Fig.  94. 


Fig-  95- 


Fig.  96. 


548 


ENGINEERING   CHEMISTRY 


2.    Microscopical  Examination. 

By  careful  manipulation  of  the  microscope,  the  fibers  of  linen, 
cotton,  and  the  various  woods  can  be  recognized. 

The  distinction  must  be  noticed  here,  however,  that  the  fibers 
from  paper,  no  matter  what  the  source,  do  not  have  the  appear- 
ance under  the  microscope  that  they  possessed  before  the  me- 


Fig.  97. 


Fig.  98. 


Fig-  99-- 


Fig.:  100. 


ENGINEERING   CHEMISTRY  549 

chanical  and  chemical  treatment  required  in  the  manufacture  of 
paper. 

The  chemical  process  in  paper-making  is  very  severe  upon  the 
various  fibers,  since  they  are  subjected  to  beating  and  cutting  in 
the  ''beating  machine,"  to  protracted  maceration  in  strong  alkali, 
to  digestion  in  boiling  water,  to  bleaching  with  chloride  of  lime, 
are  loaded  with  various  clays,  and  finally  are  sized,  and  often 
burnished. 

This  difference  between  linen  fibers  before  and  after  treatment 
is  shown  in  Figs.  93  and  94. 

A  comparison  shows  not  only  a  radical  change  in  the  form  of 
the  fibers,  but  a  difference  in  the  transparency,  due  to  removal 
of  soluble  portions  of  the  fiber. 

Poplar  wood  fiber  ( Fig.  95 )  made  by  chemical  process,  under 
the  microscope,  resembles  the  fibers  of  linen  more  than  does  any 
of  the  wood  fibers.  It,  however,  has  one  distinguishing  char- 
acteristic, even  among  the  disintegrated  pulps;  that  is,  the  tan- 
gential fragments  have  among  them  particles  bearing  a  grate,  or 
screen-like  appearance,  as  shown  in  Fig.  96. 

The  coniferous  woods  used  in  paper-making  show  peculiarities 
in  structure  entirely  different,  under  the  microscope,  from  linen 
and  cotton,  the  most  distinctive  one  being  the  small  circular  "pits" 
or  spots  along  the  center  of  each  fiber.  A  section  of  spruce 
wood,  composed  of  15  or  more  fibers,  is  shown  in  Fig.  97. 

After  pulping  and  making  into  paper,  spruce  fiber  has  the 
appearance  under  the  microscope  shown  in  Fig.  98.  It  still 
retains  the  peculiar  circular  markings,  and  is  readily  distinguished 
from  the  linen  paper  fiber,  Fig.  94,  or  from  cotton  fiber,  Fig.  99. 

In  Fig.  100  is  shown  the  peculiar  ''center-making"  of  conifer- 
ous fiber,  as  taken  from  a  sample  of  writing  paper  sold  as  linen 
paper,  but  shown  by  both  chemical  and  microscopical  examina- 
tion to  be  composed  largely  of  spruce  fiber  and  linen. ^ 

The  microscope  will  thus  determine  the  differences  between 
the  various  fibers  used  in  paper-making,  and,  by  properly  ar- 

1  The  microphotographs  used  in  this  article  are  from  specimens  made  during  an  in 
vestigation  upon  fibers  of  papers  by  Charles  S.  Schultz,  past  president  N.  Y.  Microscopical 
Soc,  and  the  writer,  and  represent  the  fibers  magnified  200  diameters. 


550  ENGINEEJRING   CHEMISTRY 

ranged  apparatus  connected  therewith,  the  percentage  of  each 
variety  of  fiber. 

According  to  the  German  official  direction  the  sample  of 
paper,  after  removal  of  sizing,  etc.,  is  to  be  steeped  in  a  solution 
of  0.2  gram  of  iodine  and  2  grams  of  potassium  iodide  in  20  cc. 
of  water  and  then  examined  under  the  microscope.  The  fibers 
may  be  conveniently  divided  into  three  groups  : 

1.  lyinen,  hemp,  and  cotton; 

2.  Wood-cellulose  ("chemical"  wood-fiber),  straw-cellulose  and 
esparto ; 

3.  Ground  wood-cellulose  and  jute. 

After  treatment  with  the  above  solution,  the  fibers  of  group  i 
are  stained  brown,  those  of  group  2  are  not  colored,  whilst  the 
strongly  lignified  fibers  of  group  3  are  colored  yellow.  But  it 
has  been  found  that  this  method  is  somewhat  defective,  the  cel- 
lulose of  group  2,  for  example,  being  invariably  to  some  extent 
stained,  whilst  the  members  of  group  i  are  so  deeply  colored  that 
it  is  almost  impossible  to  distinguish  their  structural  characters. 
After  many  experiments,  the  following  method  was  found  more 
satisfactory. 

The  paper  is  placed  on  the.  object-class  of  the  microscope  and 
treated  with  iodine  solution,  the  unabsorbed  iodine  removed  by 
means  of  filter-paper,  and  the  paper  covered  with  dilute  sulphuric 
acid.  The  solution  of  iodine  in  potassium  iodide  should  be  of 
such  a  strengh  that  a  layer  of  3  cc.  thickness  should  be  of  ruby- 
red  color  and  quite  transparent.  The  paper  is  now  removed  and 
boiled  with  a  solution  of  dilute  potassium  hydroxide,  washed 
thoroughly,  and  replaced  on  the  object-glass.  The  color  reactions 
are  as  follows : 

1.  Cotton,  linen,  and  hemp  take  a  violet  red  or  wine-red  color; 

2.  Well  bleached  wood-cellulose  and  ordinary  bleached  straw- 
cellulose  are  colored  gray-blue  or  pure  blue,  without  any  tinge 
of  red; 

3.  Unbleached  or  imperfectly  bleached  wood  fiber  absorbs  very 
little  iodine  and  remains  colorless ; 

4.  Strongly-lignified  fibers,  such  as  ground  wood  cellulose  and 
raw  jute,  are  colored  yellow. 


ENGINEERING   CHEMISTRY  55 1 

The  numbers  of  each  variety  of  fiber  are  now  carefully  counted 
by  means  of  the  microscope  and  an  eye-piece  micrometer  ruled 
in  squares.  This  chemical  treatment  and  microscopical  examina- 
tion is  to  be  repeated  upon  at  least  50  different  pieces  of  paper 
from  different  parts  of  the  sample,  and  an  average  taken.  By 
this  means  approximate  percentages  of  each  variety  of  fiber  in 
the  paper  can  be  stated.^ 

3.   Determination  of  Free  Acids  in  the  Paper. 
Free  acids  in  the  paper  may  be : 

1.  Chlorides,  from  the  hypochlorites  used  in  the  bleaching,  and 
which  have  not  been  removed  by  the  "anti-chlor ;" 

2.  Sulphuric  acid,  from  acid  alums  used  in  the  sizing. 

Free  acids  are  exceedingly  injurious  to  the  paper,  producing 
gradual  deterioration  in  the  breaking  strength,  and  also  produc- 
ing brittleness. 

The  amount  of  chlorides  can  be  determined  as  follows : 

Take  0.5  gram  of  the  paper,  cut  into  small  portions,,  and  digest 
with  50  cc.  of  boiling  distilled  water  for  two  minutes,  then  filter. 

The  filtrate  is  acidified  with  a  few  drops  of  nitric  acid,  and  the 
amount  of  chlorine  determined  by  a  tenth-normal  silver  nitrate 
solution. 

The  free  sulphuric  acid  determination  requires  the  determina- 
tion of  the  combined  sulphuric  acid  in  the  alum,  since  in  the  titra- 
ion  with  soda  solution  the  combined  acid,  as  well  as  the  free, 
is  indicated.  The  combined  acid  is  determined  indirectly  and 
then  subtracted  from  the  total  acid,  the  difference  being  the  free 
acid,  thus :  If  the  alum  used  is  potash  alum,  the  percentage  of 
potash  should  be  determined,  and  then  the  amount  of  sulphuric 
acid  and  alumina  calculated  from  the  formula  of  the  alum  (an- 
hydrous), K2AI,  (SO,)^. 

If  soda  or  ammonia  alum  be  used,  the  determination  of  the 
soda,  or  ammonia,  will  be  required.  Where  no  clay  has  been 
used  in  the  paper,  the  aluminum  can  be  determined^  instead  of 
the  other  base,  and  the  sulphuric  acid  necessary  to  form  the  alum 

1  J.  Soc.  Chem.  Ind.,  8,  564. 

2  Basic  aluminum  sulphate  forms  an  exception.  Ferguson:/.  Am.  Chem.  Soc,  16.  153, 


552  ENGINEERING   CHEMISTRY 

calculated;  this  latter  is  then  deducted  from  the  total  acid. 
Total  acid  is  thus  determined : 

Two  grams  of  the  paper  are  cut  into  small  pieces  and  digested 
with  2CX)  cc.  of  boiling  distilled  water  for  three  minutes,  then 
filtered  and  a  few  drops  of  solution  of  litmus  added.  A  solution 
of  tenth-normal  soda  is  gradually  added  from  a  burette,  until  the 
red  color  of  the  solution  turns  to  blue,  when  the  amount  of  alkali 
used  is  noted  and  calculated  to  sulphuric  acid. 

From  the  total  amount  of  sulphuric  acid  is  subtracted  the  com- 
bined sulphuric  acid  already  determined  in  2  grams  of  paper. 
This  latter  amount  is  found  by  determination  of  any  of  the 
bases,  alumina,  potash,  soda,  or  ammonia,  and  calculation  of  the 
required  acid  necessary  to  form  the  alum  used  in  the  paper. 

If  aluminum  sulphate,  AL  (804)3,  be  used  instead  of  alum, 
then  the  free  acid  and  combined  acid  will  be  the  same  in  amount, 
since  aluminum  sulphate  is  an  acid  salt,  and  titration  with  the 
soda  solution  will  give  the  amount  directly. 

4.  Determination  of  the  Nature  and  Amount  of  Sizing. 

A  paper  sized  with  rosin,  when  extracted  with  absolute  alcohol, 
gives  a  solution  which,  poured  into  excess  of  water,  yields  a 
milky  turbidity  due  to  precipitated  rosin.^  Another  test  is  based 
on  the  Raspail  reaction,  rosin  giving,  with  sugar  solution  and 
sulphuric  acid,  a  violet-red  color.  The  sugar  may  be  omitted,  as 
enough  is  formed  for  the  reaction  by  the  action  of  the  sulphuric 
acid  on  the  cellulose  of  the  paper. 

The  presence  of  animal  size  is  detected  by  treating  the  aqueous 
extract  of  the  paper  with  tannin.  The  following  fundamental 
distinction  between  papers  sized  with  rosin  and  gelatin  is  found 
to  exist.  In  the  former  the  rosin  is  distributed  uniformly 
throughout  the  substance  of  the  paper,  while  in  the  latter,  whether 
the  sizing  has  been  performed  in  the  pulp  or  sheet,  it  is  always 
found  exclusively  on  the  surface  of  the  finished  product.  This 
peculiar  property  of  gelatin  can  be  shown  by  saturating  a  plaster- 
of-Paris  slab  with  gelatin  solution  colored  suitably,  and  breaking 
it  when  dry,  on  which  it  will  be  found  to  be  colored  to  a  trifling 

1  W.  Hertzberg:  Mitt.  Konig.  tech.  Versuchs,  3,  107.    J.  Soc.  Chem.  Ind.,  9.  99. 


I 


ENGINEERING    CHEMISTRY  553 

depth,  the  inner  part  being  white.  On  these  facts  the  following 
test  is  based :  A  half-sheet  of  paper  is  repeatedly  crumpled  and 
unfolded  and  when  the  surface  has  been  thoroughly  chafed,  is 
smoothed  out  and  written  upon;  if  it  is  sized  with  rosin,  the  in- 
scribed characters  are  but  little  blurred;  while,  if  animal  size  has 
been  used  they  run  freely,  and  are  visible  from  the  opposite  side 
of  the  sheet.  J^eonhardi  has  modified  this  test,  removing  the 
doubtful  element  introduced  by  the  manual  use  of  pen  and  ink. 
A  pipette,  of  which  the  exit  is  lo  centimeters  above  the  paper, 
and  which  delivers  drops  weighing  0.03  gram  each,  is  filled  with 
a  solution  of  ferric  chloride  containing  1.531  per  cent,  of  iron. 
A  single  drop  is  allowed  to  fall  and  to  remain  on  the  paper  for 
the  same  number  of  seconds  that  i  square  meter  of  the  paper 
weighs  in  grams,  when  it  is  removed  by  blotting  paper,  and  the 
under  side  of  the  paper  brought  in  contact  with  a  plug  of  wadding 
wet  with  a  weak  solution  of  tannin;  the  production  of  a  black 
color  proves  the  iron  solution  to  have  penetrated,  and,  therefore, 
shows  the  sizing  to  be  of  animal  origin. 

Schuman's  method  for  the  determination  of  rosin  in  paper  is 
as  follows :  Two  grams  of  the  paper  are  cut  into  fine  pieces 
and  digested  below  boiling  fifteen  minutes  with  a  5  per  cent, 
solution  of  sodium  hydroxide  and  filtered. 

The  filtrate  is  made  acid  with  dilute  sulphuric  acid,  the  rosin 
separating  and  rising  to  the  surface  of  the  liquid.  This  latter  is 
filtered  upon  a  weighed  floor,  dried  at  100°  C.  to  constant  weight, 
and  its  weight  carefully  determined. 

Starch  was  used,  formerly,  as  a  sizing  for  paper,  but  in  recent 
.years  it  has  been  largely  replaced  by  rosin  size.  It  can  be  de- 
tected as  follows : 

The  paper  is  cut  into  small  portions  and  is  digested  with  boil- 
ing water  for  fifteen  minutes,  then  filtered.  To  the  filtrate  is 
added  a  drop  of  a  dilute  solution  of  iodine.  A  blue  coloration 
is  indicative  of  the  presence  of  starch. 

The  quantitative  determination  is  dependent  upon  the  conver- 
sion of  starch  into  glucose  by  means  of  dilute  sulphuric  acid, 
and  estimation  by  means  of  Fehling's  solution. 


554  ENGINEIERING   CHEMISTRY 

From  lo  to  15  grams  of  the  paper  are  digested  with  250  cc.  of 
distilled  water,  to  which  has  been  added  2  per  cent,  of  sulphuric 
acid.  Two  or  three  hours'  heating  at  100°  C.  is  sufficient  to  con- 
vert the  starch  into  glucose,  the  exact  point  being  determined  by 
taking  a  drop  of  the  solution  and  adding  thereto  one  drop  of  the 
dilute  iodine;  if  no  blue  color  is  shown,  the  conversion  is  com- 
plete. 

The  solution  is  now  made  alkaline  with  soda,  diluted  with 
water  to  500  cc,  and  two  samples  each  of  150  cc.  taken,  filtered, 
washed  well  and  treated  with  Fehling's  solution,^  as  usual  in  the 
determination  of  sugars.  Sadtler  states  as  follows  regarding  this 
test: 

"In  carrying  out  the  gravimetric  method  the  Fehling's  solu- 
tion remains  in  excess  (indicated  by  the  blue  color  of  the  solu- 
tion after  boiling),  while  the  cuprous  oxide  is  carefully  filtered 
off  and  further  treated." 

The  procedure  is  as  follows  :^ 

"Sixty  cc.  of  the  mixed  Fehling's  solution  and  30  cc.  of  water 
are  boiled  in  a  beaker,  and  the  solution  containing  the  maltose 
added  thereto  and  the  mixture  again  boiled.  It  is  then  filtered 
with  the  aid  of  a  filter  pump,  upon  a  Soxhlet  filter  (asbestos 
layer  in  a  tared  funnel  of  narrow  cylindrical  shape),  quickly 
washed  with  hot  water,  and  then  with  alcohol  and  ether,  and 
dried.  The  asbestos  filter,  with  the  cuprous  oxide,  are  now 
heated  with  a  small  flame,  while  a  current  of  hydrogen  is  passed 
into  the  funnel,  so  that  the  precipitate  is  reduced  to  metallic 
copper.  It  is  allowed  to  cool  in  the  current  of  hydrogen,  placed 
for  a  few  minutes  over  sulphuric  acid,  and  then  weighed." 

5.   Determination  of  the  Ash. 

Three  grams  of  the  paper  are  transferred  to  a  weighed  plati- 
num crucible  and  ignited  until  all  carbonaceous  matter  is  con- 
sumed.    The  amount  of  ash  is  indicative  of  the  use,  or  not,  of 

i  Tqjlen's  formula  for  Fehling's  Solution  is  as  follows:  34.639  grams  crystallized  cop- 
per sulphate  are  dissolved  in  500  cc.  water.  173  grams  Rochelle  salts  and  60  grams  sodium 
hydroxide  are  dissolved  together  in  500  cc  of  water.  Equal  volumes  of  these  solutions 
are  mixed  when  required  for  use.  Ten  cc.  of  this  Fehling's  solution  corresponds  to  0.0807 
gram  maltose— or  0.0765  gram  starch. 

2  Sadtler's  "  Industrial  Organic  Chemistry,"  p.  152. 


ENGINEJERING   CHEiMISTRY  555 

mineral  filling,  such  as  Carolina  kaolin,  to  increase  the  weight  of 
the  paper.  After  the  correct  determination  of  the  amount  of  the 
ash,  it  should  be  transferred  to  a  3-inch  porcelain  capsule,  and 
the  scheme  on  page  433  used  for  its  analysis. 

It  is  always  advisable  to  test  some  of  the  ash,  before  its 
analysis,  by  fusing  a  portion  on  charcoal  with  sodium  carbonate. 
By  this  means,  lead  or  chromium  can  be  detected,  and  then  prop- 
erly separated  in  the  analysis  of  another  portion  of  the  ash.  If 
clay  in  appreciable  quantities,  is  found,  it  will  be  necessary  to 
add  10  per  cent,  of  its  weight  as  water,  since  most  clays  contain 
from  8  to  12  per  cent,  of  water,  which,  in  the  above  instance, 
would  have  been  driven  off  during  ignition  of  the  paper  to  deter- 
mine the  per  cent,  of  ash.  If  much  iron  be  found,  Prussian  blue, 
Indian  red,  Venetian  red,  or  ochre  may  have  been  used.  If  the 
color  of  the  ash  is  blue,  ultramarine  is  present;  if  white,  silica, 
or  a  fine  quality  of  clay,  or  calcium  sulphate,  or  agalite^  may  be 
present — the  chemical  analysis  readily  showing  the  one  used  as 
a  filler. 

Ash  in  Commerciai,  Pulps. 

Per  cent. 

Sulphite    0.48 

Sulphite,  bleached    0.42 

Soda 1.34 

Soda,  bleached  1.40 

Straw    2.30 

Straw,  bleached  1.34 

Ground  wood  (pine)    0.43 

Ground  wood   (fir) 0.70 

Ground  wood   (aspen) 0.44 

Ground  wood  (lime)    0.40 

Linen    0.76 

Linen,  bleached    0.94 

Cotton    0.41 

Cotton,  bleached    0.76 

1  A  variety  of  talc— silicate  of  magnesium— in  a   finely  powdered  condition  ;  it  has  a 
very  extensive  use  as  paper  filler. 


556  ENGINEERING   CHEMISTRY 

Ash  in  Fibers. 

Per  cent. 
Cotton     0.12 

Italian  hemp 0.82 

Rhea    5.63 

Best  Manila  hemp  1.02 

Sulphite  fiber  0.46 

Fine  Flemish  flax  0.70 

China  grass   2.87 

Jute    1.32 

Esparto    3.50-5.04 

Soda  fiber 1.00-2.50 

.  If  the  ash  found  is  very  small  in  amount,  it  will  be  necessary 
to  subtract  the  amount  of  ash  corresponding  to  the  variety  of 
liber  pulp  with  which  the  paper  is  made,  to  exactly  determine  the 
amount  of  ash  belonging  to  the  added  materials. 

6.  Determination  of  the  Weight  per  Square  Meter. 
It  is  best  to  use,  when  possible,  5  different  pieces  of  the  paper 
(from  different  packages  or  rolls),  each  piece  about   i   square 
decimeter. 

These  are  placed  in  a  drying  oven  and  exposed  to  a  tempera- 
ture of  105°  C.  until  the  weight  becomes  constant.  The  weight 
of  the  five  pieces,  multiplied  by  20,  gives  the  weight  of  i  square 
meter  of  paper.^ 

7.   Determination  of  the  Thickness. 

The  thickness  of  paper  can  be  accurately  determined  by  means 
of  any  delicate  micrometer  screw. 

8.    Determination  of  Breaking  Strength. 

By  the  strength  of  a  paper  is  understood  the  measurement  of 
the  resistance  it  offers  to  breaking  or  tearing  strains.  This  re- 
sistance is  always  greater  in  the  direction  of  the  length  of  the 
web  of  paper,  as  it  is  made  on  the  paper-machine,  than  across 
the  web.  On  the  other  hand,  the  amount  of  elongation,  which 
is  measured  while  determining  the  breaking  strain,  is  greater 
in  the  direction  across  the  web  than  parallel  it.^  The  tensile 
strength  of  the  sheet,  both  across  and  parallel  to  the  web,  is  de- 
termined separately,  and  the  average  values  recorded.    To  ascer- 

1  lycitfaden  fiir  Papier-priifung,  W.  Herzberg,  Berlin,  1888. 

2  Verhandlung  des  Vereines  zur  Beforderung  des  Gewerbefleisses  in  Preussen,  1885. 


ENGINEERING    CHEMISTRY 


557 


tain  the  direction  corresponding  to  the  motion  of  the  paper- 
machine,  in  any  sample  of  machine-made  paper,  a  circular  piece 
is  cut  and  placed  on  the  surface  of  water,  when  it  will  be  ob- 
served to  roll  up.  The  diameter  of  the  disc  where  it  is  not  curved 
indicates  the  direction  of  the  length  of  the  web.  The  strips  of 
paper  used  for  ascertaining  the  tensile  strength  and  elongation 
are  cut  to  the  following  size:  i8o  millimeters  long  by  15  milli- 
meters broad.  Five  strips,  at  least,  are  taken  from  different 
sheets  and  representing  the  length  and  across  the  web,  in  order 
to  obtain  good  average  values.  These  strips  must  be  carefully 
cut;  the  edges  should  be  smooth  and  run  parallel.  Cutting  tools 
are  provided  for  this  purpose,  consisting  of  an  iron  ruler  and 
plates  of  zinc  or  glass. 

Before  determining  the  tensile  strength  and  elongation,  careful 
attention  must  be  paid  to  the  amount  of  moisture  in  the  atmos- 
phere. The  breaking  strain  of  paper  decreases  with  increase  of 
moisture  in  the  air,  while  under  the  same  influence  the  percen- 
tage amount  of  elongation  increases.  The  humidity  of  the  atmos- 
phere is  very  important  when  testing  animal-sized  paper  and 
should  on  no  account  be  overlooked.  Indeed,  the  breaking  strain 
values  can  only  be  compared  when  they  are  obtained  in  atmos- 
pheres of  equal  humidity.  The  percentage  of  atmospheric 
humidity  chosen  is  65,  because  it  is  much  easier  to  add  moisture 
to  the  atmosphere  than  abstract  moisture  from  it.  The  former 
is  done  by  boiling  water  in  the  room.  The  instrument  in  use  for 
measuring  the  humidity  of  the  air  is  the  Koppe-Saussure's  air 
hydrometer.  Before  testing,  the  strips  of  paper  are  placed  in  the 
room  for  at  least  two  hours.  The  principal  machines  in  use  for 
determining  the  breaking  strength  of  paper  are: 

The  Hartig-Reusch,  the  Wendler  and  the  Chopper  Apparatus, 
a  description  of  the  Wendler  being  given  herewith.  This  ma- 
chine is  used  for  ascertaining  the  strength  and  elasticity  of 
paper.    It  consists  in  the  main  of  four  parts  (Fig.  loi). 

1.  The  driver. 

2.  Apparatus  for  mounting. 

3.  Apparatus  for  transmission  of  power. 

4.  Apparatus  for  measuring  force  and  stretch. 


558 


engine:e:ring  chemistry 


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ENGINEERING   CHEMISTRY 


559 


560  ENGINEERING   CHEMISTRY 

The  driving  is  produced  by  a  hand-wheel,  a.  The  hub  of  this 
wheel  turns  in  the  bearing  I,  which  is  cast  in  one  piece  with  this 
bed  d.  The  screw  b,  is  led  through  this  hub,  which  is  hollow, 
and  fastened  to  the  slide  c,  and  through  its  agency  the  slide  is 
moved.  The  hand-wheel  is  equipped  with  a  bolt-nut,  consisting 
of  the  shell  p,  and  two  split  nuts,  which  may  be  opened  or  closed 
by  means  of  a  worm,  according  as  the  motion  of  the  slide  is  to  be 
produced  by  the  hand  alone  or  through  the  agency  of  the  wheel. 

The  mounting  apparatus  consists  of  two  clamps,  kk^^,  the  first 
fastened  to  the  carriage  w,  the  second  to  the  slide,  c.  Between 
the  jaws  of  these  clamps  the  paper  to  be  tested  is  stretched.  The 
jaws  of  these  clamps  are  normal  to  the  axis  of  stress.  Wave- 
shaped,  and  are  lined  with  leather,  in  order  to  prevent  the  slipping 
of  the  strip  in  the  clamps.  The  jaws  are  pressed  together  by 
means  of  the  screws,  s^  s.^. 

The  transmission  of  the  force  is  done  in  this,  as  in  most  of 
this  class  of  machines,  by  means  of  a  spiral  spring,  those  of 
Wendler's  apparatus  possessing  respectively  a  maximum  force 
of  9  and  20  kilos.  The  sp-ring  is  held  at  one  end  by  means  of  the 
shell  i,  which  is  fastened  to  the  bed  d,  at  the  other  by  the  carriage 
zv,  and  passes  through  the  shell  i.  Fastened  to  the  bed  by  means 
of  screws  are  the  catches  g,  which  work  in  the  teeth  of  the  rack, 
and  which  as  soon  as  the  paper  tears  prevent  the  spring  from 
flying  back. 

The  measurement  of  the  force  is  performed  as  follows : 

By  means  of  the  lever  h  the  carriage  pushes  the  pointer  d  be- 
fore it,  which  travels  on  the  graduated  bar  r.  The  pointer  has  a 
zero  mark  from  which,  after  the  breaking  of  the  paper,  the 
breaking  strength  is  read  in  terms  of  kilograms. 

The  measurement  of  the  elasticity  is  done  by  reading  the 
movement  of  the  pointer  in  the  opposite  direction  along  the  meas- 
uring rod  0,  graduated  according  to  the  percentages  on  a  strip 
180  millimeters  in  length.  After  the  breaking  of  the  paper,  the 
stretch  can  be  read  directly  in  per  cent. 

In  order  to  test  paper  with  this  apparatus,  one  adjusts  the 
force-measuring  rod,  by  raising  the  catches,  setting  the  spring  in 
oscilliation,  allowing  it  to  come  to  rest  and  then  carefully  sliding 


ENGINEERING   CHEMISTRY  561 

the  pointer  down  until  it  touches  the  lever.  Observe  whether  the 
zero  of  the  pointer  agrees  with  that  of  the  measuring  rod.  If 
this  is  not  the  case,  the  latter  is  moved  until  both  coincide.  The 
spring  is  now  fastened  by  means  of  a  screw  t  and  the  sled  is 
moved  until  the  zero  marks  on  both  sled  and  stretch-measuring 
rod  coincide.  Take  a  piece  of  the  paper  to  be  tested,  previously 
cut  to  standard  size,  clamp  it  in,  loosen  the  screw  t,  drop  the 
catches  and  begin  the  experiment,  giving  the  wheel  a  slow  and 
uniform  motion.  After  breaking  the  paper,  read  off  the  loading 
as  well  as  the  stretch,  relieve  the  spring  by  holding  the  carriage 
still  with  one  hand,  loosening  the  catches  with  the  other  and  al- 
lowing the  spring  slowly  to  slide  back  into  place. 

In  order  to  insert  a  new  spring,  take  the  carriage  and  by  means 
of  it  push  the  spring  in  the  direction  of  the  screw  t,  turn  the 
spring  through  90°  and  take  out  the  carriage  and  the  rack. 

In  conducting  the  experiments,  strips  i8o  millimeters  long  and 
15  millimeters  broad  should  be  used,  and  not  less  than  five  cut 
from  each  direction. 

In  order  to  render  the  result  independent  of  the  cross  section, 
use  is  made  of  the  example  of  Profs.  Reuleaux  and  Hartig. 
Using  for  the  measure  of  strength  of  paper  the  ''tearing  length," 
which  is  the  length  of  a  strip  of  paper  of  any  breadth  and  thick- 
ness, which,  if  hung  up  by  one  end,  would  break  in  consequence 
of  its  own  weight. 

Let  X  =  unknown  tearing  length  in  kilometers. 

G  =^  weight  of  the  torn  strip  (in  i8o  millimeters  length) 

in  grams. 
K  =  number  of  kilos  necessary  to  tear  strip. 

C  K 

Then —  x  =^  Kor;»;=  o. i8-^. 

0.180  G 

For  testing  materials  which  require  more  power  to  break  than 
paper,  as  for  instance  cardboard,  Schooper  has  constructed  a 
more  powerful  apparaus,  w^hich  has  a  maximum  force  of  150 
kilos.  As  the  apparatus  is  built  on  the  same  fundamental  princi- 
ples as  the  "Wendler,"  a  description  here  is  needless. 

The  methods  in  use  at  the  Bureau  for  testing  paper  at  the  Paris 
36 


562  ^  Engine:ering  che:mistry 

Chamber  of  commerce  are  as  follows  and  may  be  divided  in  to 
two  categories,  vis. : — Chemical  and  physical : — 

The  first  thing  that  the  operator  does  is  to  examine  the  nature 
of  the  fibers  that  enter  into  the  composition  of  the  pulp  from 
which  the  paper  was  made.  This  is  done  by  means  of  a  micro- 
scope. The  paper  is  first  cut  into  small  strips,  which  are  boiled 
in  a  I  per  cent,  caustic  soda  solution  that  removes  the  size.  The 
pulp  formed  is  collected  upon  wire  gauze  and  carefully  washed, 
and  then  a  few  particles  are  removed  and  submitted  to  the  action 
of  a  solution  of  iodide  of  potassium.  If,  when  the  fibers  are  ex- 
amined under  the  microscope  they  present  a  brown  color,  it 
indicates  cotton,  hemp,  flax,  or  ramie,  while  a  yellow  color  will 
indicate  the  existence  of  jute,  and  the  entire  absence  of  color 
will  indicate  alfa,  wood  pulp,  and  wood  and  straw  pulp.  The 
form  of  the  fibers  likewise  gives  indications.  Thus,  straw  will 
furnish  oblong  cells  having  a  vague  resemblance  to  the  soles  of 
shoes  and  sometimes  saw  blades.  Alfa  reveals  itself  by  very  fine 
fibers,  saw  teeth,  and  forms  resembling  those  of  the  bacilli  of 
cholera.  Cotton  shows  itself  under  the  form  of  a  ribbon  with 
swellings  and  spirals.  Wood  pulp  exhibits  itself  in  the  form  of 
very  transparent  wide  and  flat  cells. 

It  is  of  great  interest  to  know  sometimes  whether  wood  pulp  is 
present  and  how  much  has  been  used  in  the  manufacture  of  the 
paper.  In  order  to  ascertain  this  a  reagent  composed  of  a  mix- 
ture of  hydrochloric  acid  and  phloroglucine  dissolved  in  alcohol  is 
used.  The  existence  of  wood  is  at  once  revealed  by  a  rose  color. 
According  to  the  intensity  of  such  color  as  compared  with  that 
of  tests  made  previously  it  will  be  possible  to  determine  the 
quantity  of  the  wood  pulp  that  enters  into  the  composition  of  the 
paper. 

In  order  to  ascertain  the  quantity  of  materials  that  have  been 
added  to  the  pulp  to  give  the  paper  body  the  ashes  due  to  the  com- 
bustion of  the  paper  are  analyzed.  In  some  badly  prepared 
papers  there  sometimes  remains  a  certain  quantity  of  free  acids 
that  are  detrimental  to  their  preparation.  The  presence  of  these 
is  ascertained  by  making  a  very  liquid  pulp  with  distilled  water 


ENGINEERING    CHEMISTRY  563 

and  acting  upon  it  with  Congo  red,  which  becomes  blue  under 
the  influence  of  free  acids. 

In  industries  that  employ  sized  paper,  it  is  necessary  to  know 
the  composition  of  the  materials  that  have  been  used  for  the 
sizing  (gelatine,  fecula,  or  resin).  The  presence  of  fecula  is 
revealed  by  means  of  a  very  dark  solution  of  iodine  which  pro- 
duces a  blue  color.  In  order  to  see  whether  there  is  any  resin 
in  the  sample  it  is  only  necessary  to  let  a  drop  of  ether  fall  upon 
it  when  there  is  immediately  formed  an  aureole  bounded  by  a 
dull  circle.  To  ascertain  the  presence  of  gelatine  the  paper  is 
boiled  with  water,  and  the  pulp  is  filtered  and  the  filtrate  treated 
with  tannin.     The  precipitate  that  forms  is  leather. 

In  order  to  ascertain  the  degree  of  sizing  of  a  paper  a  very 
ingenious  method  is  employed.  The  sheet  is  arranged  upon  an 
inclined  plane,  and,  by  means  of  a  drop-counter,  small  quantities 
of  chloride  of  iron  are  allowed  to  fall  upon  the  upper  surface  of 
the  specimen.  The  solution  of  iron  in  flowing  leaves  a  series  of 
lines  upon  the  paper,  which  is  afterward  allowed  to  dry.  The 
sheet  is  then  turned  over,  and  the  same  operation  is  performed 
with  tannin  upon  the  under  surface  in  forming  lines  at  right 
angles  with  the  first.  If  the  paper  is  badly  sized,  there  form 
spots  of  ink  due  to  a  mixture  of  the  two  liquids  at  the  points  of 
intersection  of  the  lines.  If,  on  the  contrary,  the  sizing  is  per- 
fect, no  mixture  and  consequently  no  ink  spots  will  be  formed. 
According  to  the  blackness  of  the  latter  the  sizing  leaves  more 
or  less  to  be  desired. 

In  order  to  ascertain  the  power  of  absorption  of  blotting  paper 
there  is  employed  a  small  apparatus  (Fig.  102)  consisting  of  a 
trough  filled  with  water.  A  crosspiece  supports  a  series  of  grad- 
uated scales  against  which  specimens  of  the  paper  may  be  se- 
cured. Before  beginning  the  experiment  the  hour  is  marked. 
After  this  the  collection  of  bands  is  allowed  to  graze  the  surface 
of  the  water  for  ten  minutes,  and  the  height  of  absorption  of 
the  liquid  by  the  paper  is  noted.  Blotting  papers  differ  greatly 
from  each  other.  Thus,  in  the  same  space  of  time,  the  water  will 
rise  2.1  inches  in  one  specimen  and  3.5  in  another.     It  is  very 


564 


ENGINEERING   CHEMISTRY 


important  to  manufacturers  of  paper  to  know  the  "conditioning" 
of  the  pulp  that  they  employ,  that  is  to  say,  to  know  the  quantity 
of  water  contained  in  the  materials  that  serve  for  its  composition. 
The  apparatus  for  determining  the  resistance  of  the  materials 
to  elongation,  etc.,  is  a  dynamometric  one  that  gives  both  the 
weight  of  rupture  and  the  elongation  before  rupture  (Fig.  103). 


Fig.  102. 


The  apparatus  consists  in  principle  of  two  jaws,  the  regular 
spacing  of  which  is  obtained  by  means  of  a  winch  that  acutates 
a  screw,  and  of  a  rigid  transmission.  A  special  gearing  causes 
a  large  needle  to  displace  itself  in  front  of  a  divided  quadrant  in 
a  measure  as  the  jaws  separate  from  each  other,  and  gives  at  the 
moment  of  stoppage  an  indication  which  may  be  plainly  read, 
and  which  is  the  weight  of  the  breakage  sought.  It  will  be  un- 
derstood that  if  a  band  of  paper  be  placed  between  the  jaws  and 
the  apparatus  be  maneuvered  the  needle  will  begin  to  oscillate, 
and,  at  the  moment  of  rupture,  will  stop  in  front  of  a  division  that 
will  indicate  the  force  necessary  to  effect  a  rupture  of  the  speci- 
men considered.     An  addition  to  this  ingenious  apparatus  per- 


ENGINEERING    CHEMISTRY 


56s 


mits  at  the  same  time  of  reading  the  elongation  of  the  same 
specimen  from  the  moment  that  it  was  placed  between  the  jaws 
until  it  breaks. 


Fig.  103. 


566  ENGINEERING   CHEMISTRY. 

L^et  US  say,  by  the  way,  that  these  specimens  put  to  the  test  are 
bands  of  paper  0.5  of  an  inch  in  width.  The  tests  are  twofold 
and  are  made  upon  bands  taken  in  the  direction  of  the  tibers  of 
manufacture  and  in  a  transverse  direction.  In  fact,  the  paper 
offers  very  different  resistances  according  as  the  operation  is 
performed  in  one  direction  or  the  other.  Thus,  a  quality  of 
paper  submitted  to  the  apparatus  may  break  under  a  weight  of 
94  pounds  to  the  square  inch  taken  in  the  direction  of  the  libers 
and  under  a  weight  of  47  pounds  taken  in  a  transverse  direction. 

It  is  sometimes  very  difficult  and  even  impossible  to  recog- 
nize the  direction  of  the  fibers,  of  manufacture.  For  doing 
this  the  following  is  an  extremely  simple  process  due  to  M. 
Nickel.  From  a  sheet  of  paper,  cut  out  two  bands  0.5  of  an  inch 
in  width,  one  in  longitudinal  and  the  other  in  a  transverse  direc- 
tion, and  hold  them  together  by  one  of  their  extremities.  If  they 
be  allowed  to  fall  over  on  one  side,  the  two  hands  will  remain 
united,  but  if  they  be  made  to  fall  over  on  the  other  side  one  will 
take  on  considerable  of  a  curve,  while  the  other  will  stand  nearly 
erect.  It  is  the  latter  that  will  give  the  specimen  taken  in  the 
direction  of  the  fibers,  while  the  former  will  be  the  one  that  is 
taken  in  a  transverse  direction.  This  experiment  is  as  simple  as 
it  is  ingenious. 

Five  specimens  of  the  p^per  taken  in  each  direction  are  sub- 
mitted to  experiment,  and  averages  are  taken  for  the  results 
giving  the  weights  of  rupture  as  well  as  for  those  giving  the 
elongation. 

It  is  customary  to  indicate  the  result  in  a  figtire  that  repre- 
sents the  length  of  a  band  of  paper  that  would  be  necessary  to 
allow  the  rupture  to  take  place  by  its  own  weight.  Thus  a  speci- 
men that  breaks  under  a  weight  of  96.5  pounds  to  the  square  inch 
would  have  to  have  a  length  of  17,426  feet  in  order  to  break 
under  its  own  weight,  whatever  be  the  thickness  of  the  piece  put 
to  the  test. 

By  changing  the  jaws  of  the  apparatus  spoken  of  above,  it  is 
possible,  through  a  special  arrangement,  to  obtain  data  as  to  the 
resistance  of  the  paper  to  perforation  (see  cartouche  in  Fig.  103). 
To  this  effect  there  is  employed  an  iron  hoop  over  which  the 


ENGINEERING  CHEMISTRY 


5&7 


paper  may  be  stretched  like  the  head  of  a  drum.  The  second 
part  is  a  rounded  piston  which  rests  upon  the  taut  paper.  The 
results  give  the  weight  necessary  for  the  perforation  at  the  exact 
moment  at  which  the  latter  takes  place.  It  has  been  remarked 
that  there  is  no  relation  between  the  resistance  of  paper  to  trac- 
tion and  "the  resistance  to  perforation. 

Table  Giving  the  Weight  in  lbs.  and  ozs.  of  a  Ream  of  Paper  of 

Different  Sizes,  from  the  Weight  in  Grams  of  One  Sheet 

One  Meter  Square.  480  Sheets  to  the  Ream.  (Major.) 


Grams 
per  sq. 
meter. 

Demy 

17^X22^ 

Royal 

20X25 

Double 

Foolscap 

17X27 

Double 
Crown 

20X30 

Imperial 

22X29 

22 

X32 

25X30 

46X36 

lbs. 

ozs. 

lbs. 

ozs. 

lbs. 

ozs. 

lbs. 

OZS. 

lbs. 

ozs. 

lbs. 

ozs. 

lbs. 

ozs. 

lbs. 

ozs. 

20 

5 

6 

6 

^3 

6 

4 

8 

3 

8 

II>^ 

9 

10 

10 

4 

22 

10 

21 

5 

loi^ 

7 

3 

6 

9 

8 

9>^ 

9 

-lYi 

10 

Ij^ 

10 

12 

23 

12 

22 

15 

7 

8 

6 

W/2 

9 

0 

9 

9K2 

10 

^Vx 

II 

4^ 

24 

14 

23 

6 

3 

7 

135^ 

7 

ZV2 

9 

1V2 

10 

oYz 

II 

I 

II 

I2J^ 

26 

0 

24 

6 

IV2 

8 

3 

7 

8^ 

9 

13 

10 

iVi 

II 

8^ 

12 

i,V2 

27 

2 

25 

6 

12 

8 

8J^ 

7 

I3'/2 

IQ 

4 

10 

14% 

12 

0 

12 

12^ 

28 

% 

26 

7 

0 

8 

14 

8 

2^ 

10 

II 

II 

5% 

12 

8 

13 

4^ 

29 

27 

7 

4^ 

9 

3K2 

8 

7^ 

II 

I 

II 

12^ 

13 

0 

13 

I2J4 

30 

8 

28 

7 

8J4 

9 

9H 

8 

12^2 

II 

8 

12 

3^ 

13 

8 

14 

4^ 

31 

10 

29 

13 

9 

I3J/2 

9 

1^ 

II 

14 

12 

10% 

14 

0 

14 

12^ 

32 

12 

30 

8 

I 

10 

4 

9 

6'.^ 

12 

AM 

13 

i^ 

14 

65^ 

15 

55^ 

33 

14 

31 

8 

bV2 

10 

9 

9 

11^ 

12 

II 

»3 

8J^ 

14 

W/2 

•15 

14 

35 

0 

32 

8 

10 

10 

14 

10 

0^ 

13 

2 

13 

1554 

15 

6J4 

16 

6 

36 

2 

33 

8 

15 

II 

4 

10 

6 

13 

9 

14 

6'^ 

15 

14^2 

16 

14 

37 

4 

34 

9 

2 

II 

10 

10 

II 

13 

15 

14 

J3J^ 

16 

6 

17 

6 

38 

6 

35 

9 

7 

II 

15 

11 

0 

14 

6 

15 

5 

16 

14 

17 

14^ 

39 

9 

36 

9 

II 

12 

4J^ 

n 

5 

14 

12 

15 

12 

17 

6 

18 

6^ 

40 

II 

37 

9 

15^ 

12 

10 

II 

10 

15 

3 

16 

3 

17 

1 

18 

15 

41 

13 

38 

10 

1% 

13 

0 

II 

15 

15 

10 

16 

10 

18 

19 

7 

43 

0 

39 

10 

8 

13 

5 

12 

4 

16 

0 

17 

I 

18 

14 

19 

15 

44 

2 

40 

10 

12 

'3 

II 

12 

9 

16 

6 

17 

7 

19 

4 

20 

8 

^\ 

4 

41 

II 

0% 

14 

0 

12 

14 

16 

13 

17 

4 

19 

II 

21 

0 

46 

6 

42 

II 

5 

14 

5/2 

13 

2 

17 

4 

18 

5 

20 

3 

21 

8 

47 

8 

43 

II 

9 

14 

II 

13 

7 

17 

10 

18 

12 

20 

10 

22 

0 

48 

10 

44 

II 

nV2 

15 

I 

13 

12 

18 

0 

19 

3 

21 

2 

22 

8 

49 

12 

45 

12 

2 

15 

6H 

14 

I 

18 

6 

19 

10 

21 

10 

23 

I 

50 

14 

46 

12 

6 

15 

Il'/2 

14 

6 

18 

13 

20 

I 

22 

I 

23 

9 

52 

0 

47 

12 

10% 

16 

o^^ 

14 

II 

19 

3 

20 

8 

22 

9 

24 

I 

53 

4 

48 

12 

14^ 

16 

6 

15 

0 

19 

10 

20 

15 

23 

I 

24 

9 

54 

6 

49 

13 

3 

II 

iiH 

15 

5 

20 

0 

21 

6 

23 

8 

25 

I 

55 

8 

50 

13 

IV2 

17 

I 

15 

10 

20 

7^ 

21 

13 

24 

I 

25 

10 

56 

10 

For  500  sheets  per  ream,  multiply  the  weight  by  1.041  {i.  e.,  to  every 
lb.  add  0.66  oz.) 

For  516  sheets  per  ream,  multiply  the  weight  by  1.075  C^*  <?•>  to  every 
lb.  add  1.2  oz.) 

The  mechanical  tests  of  the  paper  are  extended  also  to  its 
thickness.  For  this  purpose  the  well-known  instrument  called  the 
Palmer  screw  gauge  is  employed.  This  gives  hundredths  of  a 
millimeter.     Different  experiments  are  made  with  packages  of 


568  ENGINEERING   CHEMISTRY 

sheets  varying  as  to  number  and  an  average  is  taken  of  the  tests 
expected.  The  weight  of  the  paper  to  the  square  foot  is  also 
determined.  This  experiment  is  made  in  order  to  ascertain  how 
many  sheets  to  lOO  pounds  will  be  obtained,  or  rather  to  find  what 
weight  of  paper  it  will  require  to  cover  a  definite  surface.  To 
make  such  a  test  it  sufiices  to  measure  a  sheet  of  paper  accurately 
and  afterward  weigh  it. 

The  following  experiment  to  which  the  paper  is  submitted 
serves  to  determine  the  resistance  to  folding,  crumpling,  and 
crushing.  This  is  very  important,  since  certain  papers,  like  those 
used  in  the  manufacture  of  bank  notes,  etc.,  pass  through  many 
hands.  It  is  therefore  necessary  before  printing  to  be  exactly 
informed  as  to  the  resistance  that  the  paper  will  present  to  use. 
Different  apparatus  have  been  devised  for  such  a  test,  but  they 
have  not  as  yet  entered  into  the  domain  of  practice.  The  most 
usual  method  is  to  operate  by  hand.  The  sheet  is  first  folded  in 
one  direction,  then  in  a  direction  at  right  angles,  and  then  diag- 
onally, and  finally  in  a  direction  at  right  angles  with  the  diagonal. 
The  specimen  that  exhibits  an  aperture  at  the  first  folding  is  con- 
sidered very  bad  and  that  which  resists  the  four  foldings  may  be 
very  good.  In  order  to  prove  its  real  resistance  it  must  be  sub- 
mitted to  new  tests.  The  specimen  is  formed  into  a  ball  and  is 
compressed.  Then  a  second  and  a  third  ball  is  made  of  it.  If 
the  paper  has  resisted  this  test  it  is  placed  between  the  two  hands 
and  submitted  to  friction.  The  majority  of  papers  do  not  resist 
such  tests.  It  has  been  found  that  there  exists  a  very  sensible 
correlation  between  the  resistance  of  the  paper  to  traction  and  its 
resistance  to  friction. 

The  tests  are  made  in  the  Bureau  that  the  Chamber  of  Com- 
merce posesses  on  Rue  de  Viannes,  and  are  accessible  to  the 
public.  Accurate  information  as  to  the  respective  qualities  of 
the  samples  may  be  obtained  by  any  one  upon  payment  of  a  small 
sum  of  money.    La  Nature,  1901. 

References. 

"C.  B.  S.  Units  and  Standard  Paper  Tests,"  an  essay  towards  establish- 
ing a  normal  system  of  paper  testing,  by  C.  F.  Cross,  E.  J.  Bevan, 
Clayton  Beadle  and  R.  W.  Sindall,  London,  1903. 


e:ngine;e:ring  chemistry 


569 


"Berichte  der  Papierpriifungs-Aiistalt,"  von  Winkler,  Leipzig. — Papier 
Zcit,  23,  1 131. 

"Mittheilungen  aiis  den  Koniglichen  technischen  Verstichs-austalten  zu 
Berlin,"  1891-1905. 

"The  Art  of  Paper  Making,"  by  Alex.  Watt,  1890. 

"Paper  Making,"  by  Clayton  Beadle,  London,  1908. 

"Papierpriifimg,"  by  W.  Herzberg,  Berlin,  1902. 

"A  Text  Book  on  Paper  Making,"  by  Cross  and  Bevan,  London,  1900. 

"The  Textile  Fibers :  Their  Physical,  Microscopical  and  Chemical  Prop- 
ties,"  by  J.  M.  Matthews,  New  York,  1905. 

"Paper  Technology,"  by  D.  W.  Sindall,  London,  1905. 


570 


ENGINEERING   CHEMISTRY 

WATER  ANALYSIS. 


Scheme  for  Water  Analysis  for  Scale  Forming  Ingredients. 

Evaporate  i  liter  of  the  water  in  a  weighed  platinum  capsule,  upon  a  water-bath  to 
dryness ;  i  transfer  to  a  hot  air-bath  and  heat  at  io5°C  for  thirty  minutes;  cool  and 
weigh.  Ignite  slowly  to  a  dull  red  heat  untii  all  carbonaceous  matter  is  consumed;  cool 
and  weigh.  The  loss  of  weight  equals  organic  and  volatile  matter.  Warm  the  contents 
of  the  capsule  with  lo  to  15  cc.  hydrochloric  acid,  and  25  cc.  water,  boil  and  filter  through 
an  ashless  filter  into  100  cc.  graduated  flask;  wash  thoroughly,  bringing  contents  of  flask 
to  containing  mark  with  water;  mix  well. 


<1)  Residue 
Consists  of 
i  n  s  o  1  uble 
mineral 
matter— 
Si  O2  or 
Si02.Al203. 
(CaSO*.) 


(3)  Residue 
Consists  of 
AlgO^Feg  O3 
dry.  Ignite, 
and  weigh 
as  such 


Si02. 


(2)  Solution. 

100  cc.  Divide  into  two  portions,  one  of  75  cc.  for 
bases  and  of  25  cc.  for  6O3.  75  cc.  Make  alkaline  with 
NH4OH,  boil  and  filter  (all  weights  obtained  to  be 
divided  by  3  and  multiplied  by  4). 


AI2O, 


FejOs 


(4)  Filtrate 

Add  solution  of  ammonium 
oxalate  :  set  aside  three  hours  ; 
then  filter. 


CaO. 


(5)  Residue  (6)  Filtrate. 
Consists  of  Acidify  with  dilute 
C  a  C2  O4.  H2SO4.  Evaporate  to 
Dry,  ignite,  dryness  in  weighed  t 
and  weigh  platinum  dish;ignite 
as  CaO.  to  expel  all  ammo-ter 
nium  salts;  cool  and 
weigh,  (MgS04  + 
Na2S04).  Dissolve  in 
water,  make  alka- 
line with  NH4OH, 
then  acid  with  HCI, 
then  alkaline  with 
NH4OH,  add  sHgl.t 
excess  of  Na2HP04 
solution,  with  con- 
stant stirring  for  two 
minutes,  set  aside 
fifteen  minutes,  fil- 
ter, wash  with  water 
containing  Vr 
NH4OH.  dry.  ignite, 
and  weigh  as 
MgoPaO:.  Convert 
this' weight  to  MgSO* 
and  subtract  from 
weight  of  MgS04  + 
NA2SO4  in  (6):  the 
difference  will  be 
NaoS04.  C  o  n  V  e  rt 
weights  to  MgO  and 
NaaO. 


SO3. 
25  CO.; 
Warm,  add 
solution  of 
b  a  r  i  u  n 
ch  1  o  r  i  d  e 
and  allow 
to  settle 
h  r  e  e 
hours;  fil- 
wash, 
dry,  ignite, 
and  weigh 
as  BaS04. 
Calculate 
to  SO3  and 
multiply 
result  by  4. 


MgO 


NajO. 


CO2 

is  found 
by  combin- 
i  n  g  the 
ch  lorin  e 

nd  sul- 
phuric acid 
with  the 


bases,  thence;  ad 
determin- 
i  ng  ho  w 
much  COo 
is  required 
to  convert 
the  rest  of 
the  CaO 
and  MgO  to 
carbonates; 
a^  shown 
in  the  ex- 
ample giv 
en  below. 


SO3 


01 

Concen. 
t  r  a  t  e  250 
cc.  of  the 
water  in  a 
porcelain 
dish  to 
about 


,  i<fa 
few  drops 
of  KjCrO* 
solution 
andtitrate 
with  a 
standard 
s  o  1  u  tion 
ot  AgNOs 
in  which 
each  cc. 
c  o  r  r  e- 
sponds  to 
0035 
gram 
chlorine. 

Multiply 
the  result 
by  4=mil- 

I  g  r  a  ms 
of  CI  per 
liter 


CO2 


CI. 


1  The  water-bath  with  constant  level  as  shown  in  Figure  116,  is  to  be  recommended. 


ENGINEERING   CHEMISTRY  57I 

To  show  in  detail  the  method  of  using  the  scheme,  the  follow- 
ing water  analysis  is  given : 

Grams. 

Platinum  evaporating  dish  +  residue  (2  liters) 56.233 

Platinum  evaporating  dish   55-035 

Residue  (2  liters)    1.198 

Grams. 

Before  ignition,  Pt.  evaporating  dish  -1-  residue 56.233 

After  ignition,  Pt.  evaporating  dish  -j-  residue 56.028 

f  Organic  and  volatile  matter  ) 

icO,  (partial)  \ °-2°5 

Grams. 

Crucible  and  SiO^ 14  942 

Crucible    14.910 

SiOa    0.032 

Solution  made  up  to   loo  cc,  75  cc.  for  bases,    ] 

25  cc.  for  SO3       J 
Twenty-five  cc. 

Grams. 

Crucible  and  BaSOj  I5-I3i 

Crucible    14.910 

BaSOi    0.221 

Seventy-five  cc. 

Grams. 

Crucible  -f  AI2O3,,  Fe20i  14.930 

Crucible    14.910 

AhOs,  Fe203   0.020 

Grams. 

Crucible  and  CaO  15.101 

Crucible    14.910 

CaO   0.191 

Seventy-five  cc. 

Grams. 

Platinum  dish  +  MgSO*  +  Na2S04 55.500 

Platinum  dish  55-030 

MgSo,  +  Na2S04  0.470 


572  ENGINEERING   CHEMISTRY 

Grams. 

Crucible  -|-  MgzP^Oi  15079 

Crucible 14.910 

MgzPaOr    0.169 

Grams. 
Equivalent  to  0.182  gram  (MgS04) 0.182 

Na2S04    ' : 0.198 

250  cc.  of  the  original  water  required  3.8  cc.  of  i/io  normal 
AgNOg  solution. 

The  calculations  are  as  follows : 
Total  residue  2  liters=  1,198  grams=o.599  gram  per  liter 

I   ?XttTcS:  (partial)    |       "     "     -.05  gran,    =o.,o.     •'       "       " 

AlgOaFegO,    1  ^  Gram 

in  7";  cc    of    '  Gram.  per  liter. 

7J      •         [-=^  of  2  liters=:(o.o2o)  then  2   liters   contain=o. 026— 0.013 

lution  J 

CaO ^  i^  .«  I.    '<  ^(0.191)  "  "  "  "  =0.254=0.127 

MgO __  ti  .»  .i    n  —^0.060)  "  "  "  *'  =0.080=0.040 

NagO ^  <<  ic  i.     a  ^(q  J25)  "  "  "  "  =0.166=0.083 

SOgin 14'"""  =^(0.0758)  "  "  "  "  =0.303=0.151 

p,          \  250  cc.  of  original  water  )  —or.-, 

^^-         }  then  calculated  to  i  liter  ^    — o-Oo3 

Undetermined =0.030 

Total 0.599 

To  convert  these  values  grams  per  liter  to  grains  per  U.  S. 
gallon  the  following  table  is  used : 


ENGINEERING   CHEMISTRY 


573 


Grains  per  Grains 

Milligrams           Imperial  per  U.  S. 

per  liter.              gallon.  gallon. 

1 0.0700  0.0583 

2 0.1400  0.1166 

3 0.2100  0.1749 

4 o.-28oo  0.2332 

5 0.3500  0.2915 

6 0.4200  0.3499 

7 0.4900  0.4082 

8 0.5600  0.4665 

9 0.6300  0.5248 

10 0.7000  0.5831 

II 0.7700  0.6414 

12 0.8400  0.6998 

13 0.9100  0.7581 

14 0.9800  0.8165 

15 1.0500  0.8747 

16 1. 1200  0.9330 

17 1. 1900  0.9914 

i2 1.2600  1.0497 

19 1.3300  1. 1080 

20  1.4000  1. 1663 

21 1.4700  1.2246 

22 1.5400  1.2829 

23 1.6100  1. 3413 

24 1.6800  1.3996 

25 1.7500  1.4579 

26 1.8200  1. 5162 

27 1.8900  1.5745 

28 -.  1.9600  I  6329 

29 2.0300  1.6912 

30 2.1000  1.7495 

31 2.1700  1.8078 

32 2.2400  1. 8661 

33 2.3100  1.9244 

34 2.3800  1.9828 

35 2.4500  2.0411 

36 2.5200  2.0994 

37 2.5900  2.1577 

38 2.6600  2.2160 

39 2.7300  2.2745 

40 2.8000  2.3327 

41 2.8700  2.3910 

42 2.9400  2.4493 

43 3.0100  2.5076 

44 3.0800  2.5659 

45 3.1500  2.6243 

46 3.2200  2.6826 

47 3.2900  2.7409 

48 3.3600  2.7992 

49 3.4300  2.8575 

50 3.5000  2.9159 


Grains  per  Grains 

Milligrams           Imperial  per  U.  S. 

per  liter.               gallon.  gallon. 

51 35700  2.9742 

52 3.6400  3.0325 

53 3.7100  3.0908 

54 3.7800  3.1491 

55 3.8500  3.2074 

56 3.9200  3.2658 

57 3.9900  3.3241 

58 4.0600  3.3824 

59 4- 1300  3.4407 

60 4.2000  3.4990 

61    4.2700  3.5573 

62 4- 3400  3.6157 

63 4.4100  3.6740 

64  ....  4.4800  3.7323 

65   4.5500  3.7906 

66     4.6200  3.8489 

67 4.6900  3.9073 

68  4.7600  3.9656 

69 4.8300  4.0239 

70 4.9000  4.0822 

71 4.9700  4.1405 

72 5.0400  4.1988 

73 5.1100  4.2572 

74 5.1800  4.3155 

75 52500  4.3738 

76 5.3200  4.4321 

77 5- 3900  4.4904 

78 5.4600  4.5488 

79 5.5300  4.6071 

80 5.6000  4.6654 

81 5.6700  4.7237 

82 5.7400  4.7820 

83 5.8100  4.8403 

84 5.8800  4.8987 

85 5.9500  4.9570 

86 6.0200  5.0153 

87 6.0900  50736 

88 6.1600  5.1319 

89 6.2300  5.1903 

90 6.3000  5.2486 

91 6.3700  5.3069 

92 6.4400  5.3652 

93 6.5100  5.4235 

94 6.5800  5.4818 

95 6.6500  5.5402 

96 6.7200  5.5985 

97 6.7900  5.6568 

98 6.8600  5.7151 

99 6.9300  5.7734 

■  00 7.0000  5.8318 


574  ENGINEERING   CHEMISTRY 

The  result  being:  L^Tglfi^n 

SiOz    0.93 

AUOs-Fe^Oa    0.75 

CaO    740 

MgO    2.33 

NaaO   484 

SO3  , 8.80 

CI  '..: 3-09 

Organic  anci  volatile,  etc 5.94 

Undetermined    0.81 

Total  residue    3489 

Before  uniting  these  in  chemical  combination,  it  is  necessary  to 
determine  the  amount  of  sulphates,  soluble  and  insoluble,  in  the 
water  so  as  to  combine  properly  the  sulphuric  acid.  Five  hun- 
dred cc.  of  the  water  are  evaporated  to  dryness  in  a  platinum 
dish,  ignited,  cooled,  and  residue  treated  with  small  amounts  of 
boiling  water  with  filtering;  total  filtrate  should  not  exceed  50 
cc.  Acidify  with  a  few  drops  of  HCl,  add  10  cc.  solution  of 
BaCl.2,  set  aside  ^2  hour,  then  filter,  wash  well  with  water,  dry, 
ignite  and  weigh. 

Crucible  and  BaS04   15077  grams. 

" 14.908      " 

BaSOi 0.169  gram  for  J/^  liter  water. 

"       0.338       "         "     I      " 

.0.338  BaS04  =^  0.1 16  gram  SO3.  This  amount  (0.116  gram) 
represents  the  SO3  that  is  combined  to  form  soluble  sulphates, 
and  the  amount  combined  to  form  insoluble  sulphates  is  found  by 
subtracting  0.116  gram  from  0.151  gram  (total  SO3)  found, 
giving  0.035  gram  to  unite  with  the  CaO  to  form  CaS04. 
Converting  from  grams  per  liter  to  grains  per  gallon : 

Total  SO3  =  0.15 1  gram  per  liter  =  8.80  grains  per  gallon. 

I  SO3  for 

-^soluble         y    ^=0.116     "        "       "      =6.76 


1 


(  sulphates 

^     IIISUIUUIC         V 

(sulphates   J 
The  combinations  are  usually  made  as  follows : 


( SO3  for 

'  insoluble     \    =  0.035     "        "       "      =  2.04 


e)ngine:e:ring  chemistry 


575 


The  chlorine  is  combined  with  the  sodium;  if  in  excess  the  re- 
mainder with  the  magnesium.  The  sulphuric  acid  determined  as 
insoluble  salt  is  combined  with  calcium,  the  soluble  with  the 
sodium,  and  if  any  remains  uncombined,  with  the  magnesium. 
The  oxides  of  calcium  and  magnesium  remaining  uncombined  are 
united  with  COo,  forming  carbonates.     Thus : 

Grains  per 
gallon 

SiOz 0.93 

ALOs.FcaO;    0.75 

NaCl    5.09 

CaS04   3,46 

Na^SO,    4.39 

MgS04    6.43 

CaCOs    10.68 

MgCO,    0.39 

Organic  matter   1.96 

Undetermined    0.81 

Total    34.89 


If  it  be  desired  to  determine  the  composition  of  the  insoluble 
matter  in  the  water  as  well  as  to  include  the  potash  salts  that  may 
be  present,  the  following  scheme  is  used : 


CO     aZo 

s  ^  - 

^     o  ^  a 
P5     *  c  -  « 

pq      O  eS'c  ^ 

eti  U  ^  C 
u)  O  '^  <S 


S    =    O    V. 


p  c 


0^  y 


H 

S    :5~.  8 

f     «  y  w  « 

o  -Si-?! 

K      5  rt  ^  2J 

O     =^5£ 
-  0^2 

si's 


^5  »-5  5.5 

g  S  C  ^^4j 

8     8^S'?5 


.582 


U    CS   U    IT    II 


8-0 


ill 
r  «  c 

11  •/  c 

;  '-'^  »o 
i     .5  >> 

t^T3 


a; 


o  ^  >« 

t/2  O  t- 


O 

B 

a 

ctt 

o 

C 


rt    _  3  «  0  o 


""•s:'^ 


3.S 


«5  JJ  oi  d' 

(LI  I'  r:  »'  >  n  <*^ 

2  ^      o4;5?TO 
S    rt  ^  .ti  g-  be  o  rt 

V-.-y-r"i03 

«  HvCPbfiO  ^  o  cr 

■ — -        .^  .^   01   »  <^  D 


3    wQ 


h-o 


8  o  o  a 


:-T3.= 


i"  n  ?"  «? 


>>0  CO. 


-a  B'/r,--^ 

II 


Ov.- 
O  o 


a  w  a:i2ii'^•- 
-S'Oj'S  «  a 

bi^s^'^'^i 

t  0^  P  CS  "^      ^- 


fr9  <"  P 

P  «     ao 
~  c  a  o2 


21-' 


^■ou 


rt^iSi- rt 


'oJ.^Sf  g 


O  W) 
bc^' 
^2 


--^^a'^O 


.    a-O  a.  II    .'O 

•5  u  «  ^  >  i:  X 


o 


2  « 
fa 


■«      P     5S5,boj-- 


.  .^  r  Qfi  CO  ™ 
'*P  bC--cjO 


^^03    , 


S^^  K  o  u  a  « 
c8  xJS'O  cbU 


o« 


d  i « 


5  <Jt: 


'ej5 

bcbt 

«  T.'S 

I  o  i  ^ 

»        coco 


9. 

5 


P  CIJ 


P      CO 


S   o  .ti 


KNGINDEJRING   CHEMISTRY  577 

To  show,  in  detail,  the  method  of  using  the  scheme,  the  fol- 
lowing water  analysis  is  given.  (Preliminary  tests  having  shown 
the  water  to  contain  but  little  residue,  8  liters  of  it  were  evap- 
orated.) 

Grams 

Platinum  capsule  and  residue  (8  liters) 147.460 

Platinum  capsule  without  residue 146.620 

Total  residue   0.840 

Before  ignition,  capsule  and  residue 147.460 

After  ignition,  capsule  and  residue 147.197 

Organic,  volatile  (CO2),  etc 0.263 

Crucible  -f -  Si02 15-970 

Crucible    15.904 

SiOi    0.066 

Solution  made  to  100  cc. — 75  cc.  for  bases,  25  cc.  for  SO3. 

Twenty-five  cc.    (SCO-  Grams 

Crucible  and  BaSO* 16.023 

Crucible    15.903 

BaSOi 0.120 

Seventy-five  cc.  Grams 

Crucible  +  Fe^OsiAWs)    159338 

Crucible    15903 

Fe^OsCAlaOs)    0.0308 

Crucible  -f  CaO   16.0197 

Crucible    15.903 

CaO   0.1167 

Platinum  dish  -)-  alkaline  sulphates  -f-  MgS04...   53.443 
Platinum  dish   53-197 

Sulphates    0.246 

Dissolved  in  water,  made  solution  up  to  50  cc. — 25  cc.  for  mag- 
nesia determination,  and  25  cc.  for  potash  determination. 

Grams 

Crucible  -f  Mg2P207   15-976 

Crucible    15904 

Mg2P207   0.072 

0.072     X     2    =    0.144    Mg2P20T. 

Mg2P207  :  (MgS04)2  ::  0.144  :  -s: 
MgSOi  =  0.155  gram. 

37 


578  ENGINEERING   CHEMISTRY 

Potassium  platinichloride  on  counterpoised  filters  =:  0.023 
gram,  corresponds  to  0.017  gram  potassium  sulphate  in  the  50  cc. 

Having  determined  the  amounts  of  magnesium  and  potassium 
sulphates,  the  residue  remaining  is  sodium  sulphate,  as  follows : 

Grams 

Total  sulphates    0.246 

Magnesium  sulphate  0.155 


Sodium  and  potassium  sulphates 0.091 

Potassium  sulphate   0.017 


Sodium  sulphate   0.074 

and  calculated  to  their  oxides  would  be : 

MgO  =  0.051  gram  for  75  cc.  =:  0.068  gram  for  100  cc.  or  the  8  liters. 
Na20  =  0.032  gram  for  75  cc.  =  0.042  gram  for  100  cc.  or  the  8  liters. 
K2O    =  0.009  gram  for  75  cc.  =  0.012  gram  for  100  cc.  or  the  8  liters. 

The  chlorine  found  by  titration  amounted  to  0.0055  gram  per 
liter. 

The  weights  thus  obtained  are  in  terms  of  the  total  residue, 
8  liters,  and  are  converted  into  values  corresponding  to  i  liter, 
the  result  being  as  follows : 

Grams  per  liter 

SiOz    0.0082 

SO.S  — 0.0205 

CI 0.0055 

K2O    0.0015 

Na20   0.0052 

MgO    0.0085 

CaO    ' 0.0194 

Fe203(Al20.)     0.0051 

Organic,  CO2,  etc 0.0320 


0.1059 
Oxygen  in  excess  of  CI 0.0014 


Total  residue   ^ 0.1045 

It  now  becomes  necessary  to  unite  these  in  chemical  union,  as 
near  as  possible,  as  they  exist  in  the  water;  the  following  is  ob- 
tained : 


ENGINEERING   CHEMISTRY  579 

Gram  per  liter 

NaCl    0.0091 

Na2S04   0.0009 

K2SO4    0.0027 

CaS04  0.0321 

CaCOs    o.oi  10 

MgCO.<i   0.0178 

Fe203,AU03    0.0050 

Si02 0.0082   , 

Organic,  etc o.oi  ^^ 

Total   o.  1045 

and  converting  these  values  into  grains  per  gallon,  we  obtain : 

Grains  per 
U.  S.  gallon 

NaCl    0.5306 

Na2S04    : 0.0525 

K2SO4    0.1574 

CaSO*    1.8720 

CaCOs    0.6415 

MgCO.   1.0380 

Fe203,Al20.{    0.2915 

Si02  0.4782 

Organic  matter   i  .0322 

Total   6.0939 

This  analysis  shows  that  the  principal  scale-forming  ingredient 
is  calcium  sulphate,  being  more  than  equal  to  the  calcium  and 
magnesium  carbonates. 

The  following  analysis  is  of  a  water  containing  sulphuric  acid, 
but  the  alkalies  being  present  in  sufficient  amount  to  combine  with 
all  of  it,  as  well  as  the  chlorine,  no  calcium  sulphate  is  present : 

Gram  Grains 

per  liter  per  gallon 

SiOa     0.0038  0.2215 

SO3  O.OI  10      0.6414 

CI  0.0062      0.3615 

K2O     0.0033  0.1923 

Na20   0.0185  1.0788 

MgO    0.0165  0.9624 

CaO    0.0466  2.7175 

Al203,Fe203    0.0020  0.1166 

CO2    0.0530  3.0908 

Organic    0.0246  1-4345 

0.1855  10.8173 

Oxygen  in  excess  of  CI 0.0021  0.1224 

Total   0.1834  10.6949 


580  ENGINEERING   CHEMISTRY 

Combined  as  follows : 

Gram  Grains 

per  liter  per  gallon 

NaCl   0.0154  0.8980 

Na2S04    0.0141  0.8223 

K2SO4    0.0061  0.3557 

CaCO^    0.0833  48577 

MgCOa   0.0339  1.9768 

Al203,Fe203    0.0020  0.1 166 

Si02    0.0038  0.2215 

Organic   0.0246  14345 

Total   0.1832  10.6831 

Where  all  the  chlorine  is  not  in  combination  with  the  sodium 
and  potassium,  magnesium  chloride  is  usually  present. 

The  latter  compound,  while  not  scale-forming,  is  considered 
as  an  active,  corrosive  agent,  upon  the  supposition  that  at  the 
temperature  of  100°  C.  and  higher,  it  is  decomposed,  and  hydro- 
chloric acid  formed  and  liberated. 

The  analysis  given  below,  is  of  a  water  from  a  driven  well  in 
Florida.  Complaint  having  been  made  that  not  only  was  the 
scale  excessive  in  amount,  but  that  corrosive  action  was  also  very 
marked,  analysis  was  made,  reference  to  which  readily  explains 
the  difficulty  encountered  in  the  boilers. 

Gram  Grains 

per  liter  per  gallon 

NaCl   0.323  18.83 

KCl    0.067  3.91 

MgCL    0.104  6.06 

CaSOi    0.197  11.49 

CaCOs    0.293  17.08 

MgCOa    0.144  8.40 

Si02    o.oii  0.64 

Al203,Fe203    0.007  0.41 

Organic    0.138  8.05 

Total   1.284  74-87 

In  all  of  the  above  analyses  the  constituents  have  been  stated 
in  grains  per  gallon,  rather  than  in  parts  per  100,000,  the  for- 
mer being  in  general  use  by  the  mechanical  profession  as  the 
proper  method  by  which  to  express  the  weights  of  the  component 
parts  of  the  residue  of  a  water. 

The  following  is  an  analysis  of  boiler  water,  in  which  no  scale 


ENGINEERING   CHEMISTRY  581 

was  present,  but  where  corrosion  was  rapid.     The  sample  was 
marked  ''Stand  Pipe  in  Boiler :" 

Grains  per 
gallon 

NaCl 33.70 

KCl    2.26 

NazSO* 16.33 

MgS04    19.26 

Fe20a  (suspended  particles)    5.64 

Fe2(N03)2   6.12 

CuCNOs)^ 3-i8 

Ca(N03)=  12.11 

Mg(N03)2    14.08 

Silica    14.16 

HNO3  (free)    12.27 

Organic  matter  24.12 

Undetermined    2.15 

Total  164.38 

The  water  supplied  to  this  boiler,  also  acid,  was  composed  as 
follows : 

Grains  per 
gallon 

NaCl 0.73 

MgCl2  (KCl)    0.87 

MgS04    1.71 

CaS04  1.53 

Ca(N03)2   0.38 

SiOz    0.52 

Fe2(N03)2   0.44 

HNO3  (free) 0.90 

Organic  matter  ; 0.64 

Total  solids   '].^2. 

By  neutralizing  the  free  acid,  in  the  water  supply,  with  sodium 
carbonate,  corrosive  action  in  the  boiler  was  prevented. 

In  coal-bearing  districts  the  boiler  waters,  while  usually  selected 
with  care  regarding  the  total  solids,  often  contain  free  sulphuric 
acid,  derived  from  the  oxidation  of  the  iron  pyrites  in  the  coal 
beds  and  which  enter  into  the  water  supply. 

Fre€  Acid. 

The  free  acid  in  water  can  be  determined  quantitatively  as 
follows : 
250  cc.  of  the  water  are  transferred  to  a  6-inch  porcelain  evap- 


582  ENGINEERING   CHEMISTRY 

orating  dish,  a  few  drops  of  litmus  solution  added/  and  the  water 
boiled  five  minutes,  then  titrated  with  a  very  dilute  standard  solu- 
tion of  caustic  soda. 

Thus :  250  cc.  water  taken,  which  required  1.2  cc.  of  the  caustic 
soda  solution. 

The  caustic  soda  solution  is  of  such  a  strength  that  31.1  cc.  of 
it  neutralizes  5  cc.  of  normal  sulphuric  acid  solution. 

One  cc.  of  the  normal  sulphuric  acid  solution  contains  0.049 
gram  sulphuric  acid. 

Then  i  cc.  of  the  dilute  caustic  soda  solution  corresponds  to 
0.00787  gram  sulphuric  acid. 

If  250  cc.  of  the  water  required  1.2  cc.  of  the  caustic  soda 
solution,  one  liter  will  require  4.8  cc.  caustic  soda  solution  = 
0.0377  gram  sulphuric  acid,  corresponding  to  2.20  grains  of  free 
sulphuric  acid  per  gallon  of  water. 


SCHEME  FOR  THE  RAPID  ANALYSIS  OF  BOILER  WATERS 
FOR  SCALE-FORMING  INGREDIENTS. 

One-half  liter  of  the  boiler  water  is  evaporated  to  dryness  in  a 
weighed  platinum  dish  and  the  amount  of  residue  determined. 
This  residue  is  treated  with  a  solution  of  alcohol  66  parts,  and 
water  34  parts,  and  then  filtered.  The  undissolved  matter  is  des- 
ignated as  scale-forming  material.  This  method  gives,  of  course, 
the  total  matter  that  is  scale- forming,  but  does  not  indicate  the 
proportions  of  each  constituent. 

It  is  essential  to  know,  in  many  cases,  whether  the  scale  will  be 
calcium  sulphate  or  calcium  carbonate  or  magnesium  carbonate. 

The  scale  formed  by  calcium  sulphate  is  hard,  compact  and 
exceedingly  difficult  of  removal,  whereas  the  scale  formed  by 
calcium  and  magnesium  carbonates  is  more  or  less  porous  and 
not  difficult  of  removal. 

The  following  scheme,  used  by  the  author,  has  the  advantages 
of  correctness  and  rapidity: 

1  Phenolphthalein  can  also  be  used,  with  this  precaution.  Upon  adding  a  few  drops 
of  the  phenolphthalein  solution  to  the  water,  no  coloration  takes  place,  since  the  COo  in 
the  water  prevents  the  action  of  the  phenolphthalein,  but  upon  boiling  and  expelling  the 
CO2  the  red  color  will  appear.  If  upon  boiling  the  water  ten  minutes  no  red  coloration 
appears,  the  water  may  be  considered  acid  and  the  soda  solution  used  until  the  red  color 
appears. 


ENGINEERING    CHEMISTRY 


583 


584  ENGINDEJRING   CHEMISTRY 

The  remaining  CaO  as  well  as  the  MgO  are  calculated  to  car- 
bonates and  the  amounts  of  CaS04,  CaCOg.MgCOa,  SiO^,  etc., 
and  AlgOs-FegOg,  should  equal  the  weight  of  residue  (3). 

Prof.  Main  states  regarding  the  above  scheme,  as  follows : 

"Careful  tests  made  with  artificial  mixtures  of  sulphate  of 
lime  and  carbonate  of  lime  show  that  the  error  due  to  solubility 
of  calcium  sulphate,  in  water,  is  hardly  weighable,  especially  after 
it  is  converted  into  anhydrous  sulphate  by  heat. 

"The  amount  of  sulphate  of  lime  which  will  fail  to  precipitate 
from  solution  and  that  which  can  be  dissolved  (in  any  reasonable 
time)  from  the  solid  state,  with  pure  water  alone,  are  very  dif- 
ferent things.  This  supposed  solubility  has  previously  prevented 
chemists  from  using  methods  similar  to  the  above  science  for  a 
rapid  method  of  boiler  water  analysis." 


DETERMINATION  OF  THE  HARDNESS  OF  WATER. 

The  hardness  of  water  may  be  temporary,  permanent,  or  both. 

The  former  is  caused  by  calcium  and  magnesium  carbonates 
which  are  held  in  solution  by  the  excess  of  carbon  dioxide  in  the 
water. 

Boiling  the  water  drives  out  the  excess  of  the  carbon  dioxide 
and  the  calcium  and  magnesium  carbonates  are  thereby  precip- 
itated. 

The  permanent  hardness  is  usually  caused  by  calcium  sulphate, 
which  is  not  precipitated  by  boiling,  or  by  magnesium  chloride. 
The  former,  however,  can  be  separated  out  of  boiler- feed  water 
by  heating  240°  F.,  since  it  is  then  insoluble. 

Temporary  Hardness. 

The  temporary  hardness  is  determined  as  follows :  Standard 
sulphuric  acid  solution  and  standard  sodium  carbonate  solution 
are  required  and  are  prepared  as  follows : 

1.06  grams  of  pure  ignited  sodium  carbonate  are  dissolved  in 
one  liter  of  distilled  water.  One  cc.  =  0.00166  gram  correspond- 
ing to  o.ooi  gram  calcium  carbonate.  The  standard  sulphuric 
acid  solution  is  made  of  such  strength  that  i  cc.  of  it  exactly 
neutralizes  i  cc.  of  the  standard  sodium  carbonate  solution. 


EJNGINEJERING   CHEMISTRY  585 

One  hundred  cc.  of  the  water,  to  which  a  few  drops  of  lacmoid 
solution^  have  been  added,  are  heated  to  boihng,  and  the  sul- 
phuric acid  gradually  added  until  the  color  changes. 

Each  cubic  centimeter  used  represents  one  part  of  calcium  car- 
bonate per  100,000  parts  of  water,  or  if  it  be  desired  to  express  it 
in  grains  per  gallon,  the  results  in  parts  per  100,000  is  multiplied 
by  0.583. 

Permanent  Hardness. 

One  hundred  cc.  of  the  water  are  taken  and  an  excess  of  the 
sodium  carbonate  is  added  thereto, — generally  speaking,  the  same 
volume  will  be  sufficient.  This  is  evaporated  to  dryness  in  a 
platinum  dish,  and  the  soluble  portions  are  extracted  with  dis- 
tilled water  through  a  small  filter  and  the  filtrate  is  titrated  with 
the  standard  acid  for  the  excess  of  sodium  carbonate ;  the  differ- 
ence represents  the  permanent  hardness. 

Reference. 

Consult  Sutton's  "Volumetric  Analysis,"  p.  67.     Alkalinity  and  Free  CO2, 
etc.,  Jour.  Soc.  Chcm.  Ind.,  Jan.  15,  1904. 

Determination  of  Hardness  by  the  Soap-Test.^ 

The  degree  of  hardness  of  a  water  is  determined  by  ascertain- 
ing the  amount  of  standard  soap  solution  necessary  to  form  a 
permanent  lather  with  a  definite  volume  of  the  sample;  the 
''harder"  the  water  the  more  soap  it  will  consume,  owing  to  the 
formation  of  insoluble  calcium,  magnesium,  etc.,  soaps  ("curd"), 
brought  about  by  the  decomposition  of  the  soda  or  potash  soap 
added,  by  the  salts  of  the  alkaline  earths  present  in  the  water. 

The  hardness  of  water  is  usually  expressed  in  terms  of  calcium 
carbonate. 

Preparation  of  the  standard  solution : 

I.  Solution  of  "hard  water." — ^Dissolve  i.ii  grams  of  pure 
fused  calcium  chloride  in  a  little  water,  and  dilute  to  one  liter  at 
15°  C,  or  dissolve  i  gram  of  pure  calcium  carbonate  in  50  cc.  of 
dilute  hydrochloric  acid,  evaporate  to  dryness,  dissolve  in  50  cc. 
of  water,  and  dilute  to  one  liter.     In  either  case  each  cubic  cen- 

1  Made  by  dissolving  2  grams  lacmoid  in  1,000  cc.  of  dilute  alcohol  (50  per  cent.). 

2  H.  Joshua  Phillips. 


586  ENGINEERING   CHEMISTRY 

timeter  of  the  solution  will  correspond  to  o.ooi   gram  calcium 
carbonate. 

2.  Solution  of  soap. — Castile  soap,  which  is  supposed  to  be 
made  with  soda  and  olive  oil,  is  much  used  for  standard  soap  so- 
lutions, but  it  has  been  found  liable  to  considerable  deterioration 
on  keeping-,  especially  in  cold  weather,  owing  to  the  deposition 
of  sodium  palmitate. 

Sodium  oleate  makes  a  standard  soap  solution  which  suffers 
very  little  change  on  keeping,  and  can  be  generally  recommended 
for  the  purpose. 

Thirteen  grams  of  it  are  dissolved  in  a  mixture  of  500  cc.  of 
alcohol  and  500  cc.  of  water,  and  filtered  if  necessary.  It  now 
becomes  necessary  to  standardize  it,  so  that  i  cc.  will  be  equiva- 
lent to  O.OOI  gram  of  calcium  carbonate.  In  order  to  effect  this, 
12  cc.  of  the  standard  hard  water  are  run  into  a  250  cc.  stoppered 
bottle  from  a  burette  and  diluted  to  58.3  cc.  A  burette  is  now 
filled  with  the  soap  solution  which  is  run  into  the  bottle  i  cc.  at 
a  time,  and  the  bottle  vigorously  shaken  after  each  addition,  until 
a  point  is  reached  where  a  persistent  lather,  lasting  for  at  least 
five  minutes,  is  obtained.  Note  the  volume  required.  Twelve 
cc.  of  hard  water  should  require  13  cc.  of  soap  solution  (distilled 
water  itself  requiring  i  cc.  to  form  a  lather),  but  it  wnll  be  a 
figure  less  than  this,  and  therefore  the  soap  solution  is  too  strong 
and  will  require  diluting,  so  that  12  cc.  of  a  standard  ''hard" 
water  will  require  13  cc.  of  the  soap  solution.  An  example  of  an 
actual  preparation  of  a  standard  soap  solution  will  explain  this. 

Thirteen  grams  of  sodium  oleate  were  dissolved  in  a  mixture 
of  500  cc.  of  alcohol  and  500  cc.  of  water,  and  filtered.  On  test- 
ing in  the  manner  described,  12  cc.  of  the  standard  "hard"  water 
diluted  to  58.3  cc.  required  11.4  cc.  of  the  soap  solution  to  form  a 
persistent  lather. 

Now,  since  13  cc.  should  have  been  required,  every  11. 4  cc.  of 
the  soap  solution  left,  requires  diluting  by  13  —  11. 4  :=  1.6  cc. 

Suppose  there  were  960  cc.  of  the  solution  left,  therefore  — —  = 

II. 4 

84.2,  and  84.2  X  1-6  =  134-7  cc.  more  of  the  mixture  of  alcohol 


ENGINEERING    CHEMISTRY 


587 


and  water  to  be  added.  On  adding  this  quantity,  thoroughly 
mixing,  and  testing  as  before,  12  cc.  of  the  standard  hard  water 
required  exactly  13  cc.  of  the  soap  solution. 

Determination  of  Total  Hardness. 

58.3  cc.^  of  the  clear  sample  of  the  water  to  be  examined,  are 
run  into  a  250  cc.  flask,  and  the  standard  soap  solution  added  in 
the  manner  described  above,  until  a  lather  capable  of  persisting 
for  five  minutes,  is  produced.  The  number  of  cubic  centimeters 
required  will  give  the  degree  of  hardness  in  terms  of  calcium 
carbonate  in  grains  per  gallon. 

Or,  take  100  cc.  of  the  water,  transfer  to  a  flask,  and  add 
standard  soap  solution  as  usual.  Suppose  the  100  cc.  of  water 
required  5.1  cc.  soap  solution.  Then  1,000  cc.  of  water  would  re- 
quire 51  cc.  soap  solution  equivalent  to  0.051  gram  of  calcium 
carbonate  per  liter,  or  5.1  parts  per  100,000,  or  2.97  grams  cal- 
cium carbonate  per  United  States  gallon. 

If  the  water  contains  a  fair  proportion  of  magnesium  salts, 
there  will  be  some  difficulty  in  obtaining  the  right  point,  owing 
to  the  slowness  with  which  magnesium  salts  decompose  soap;  an 
apparently  persistent  lather  is  formed,  which,  on  being  allowed  to 
stand  a  little  while  and  again  shaken  up,  will  disappear;  a  little 
experience  with  magnesian  hard  waters  will  familiarize  the  oper- 
ator with  this  peculiarity. 

The  Permanent  Hardness. 

Two  hundred  and  fifty  cc.  of  the  water  are  poured  into  a  500 
cc.  flask,  and  boiled  for  one-half  hour,  the  original  voKime  being 
kept  up  by  frequent  additions  of  boiled  distilled  water,  free  from 
carbon  dioxide. 

After  cooling  it  is  quickly  poured  into  a  250  cc.  graduated  stop- 
pered flask,  diluted  if  necessary  to  exactly  250  cc.  at  15°  C.  with 
distilled  water,  well  mixed  and  filtered.  58.3  cc.  of  the  solution 
are  now  poured  into  the  bottle  and  the  permanent  hardness  deter- 
mined as  described. 

1  If  it  be  desired  to  determine  the  hardness  in  grains  per  English  Imperial  gallon, 
instead  of  the  United  States  gallon,  70  cc.  of  the  water  must  be  taken.  This  is  dependent 
upon  the  fact  that  the  English  Imperial  gallon  contains  70,000  grains,  and  the  United 
States  gallon  58,318  grains. 


588  ENGINEERING   CHEMISTRY 

The  Temporary  Hardness. 

The  temporary  hardness,  or  that  hardness  removed  by  boiUng, 
is  obtained  by  deducting  the  degree  of  permanent  hardness  from 
that  of  the  total. 

Standards  of  Hardness.^ 

The  French  standard  of  hardness  of  water  is  stated  in  terms  of 
milligrams  of  calcium  carbonate  in  100  grams  of  water,  or  parts 
calcium  carbonate  per  ioo,ocx)  parts  of  water. 

The  German  standard  represents  milligrams  of  lime  in  100 
grams  of  water,  or  parts  lime  per  100,000  parts  of  water. 

The  English  standard  represents  grains  of  calcium  carbonate 
per  gallon  of  70,000  grains. 

The  American  standard  represents  grains  of  calcium  carbonate 
per  gallon  of  58,381  grains. 

Tabi,e  Showing  the  Rei^ative  Hardness  oe  the  Water  Suppeied  to 
Cities.    Determination  Made  by  A.  R.  Leeds,  Ph.  D. 


Calcium 

1  ■ 

i 

a 

>> 
0 

1 

<LI 

« 

carbonate 

Ah 

? 
^ 
^ 

8 
m 

0 

1 

5 

I 

u 

Parts  per  roo.ooo. . . 

4.4 

3-3 

2.2 

3-2 

2.1 

4.8 

5-5 

6.4 

Grains  per  U.  S.  gal. 

2.56 

1.92 

1.28 

1.86 

1.22 

2.79 

3.20 

3-73 

THE  SANITARY  ANALYSIS  OF  WATER. 

This  comprises  the  determination  of 

1.  Chlorine; 

2.  Free  and  albuminoid  ammonia; 

3.  Nitrates; 

4.  Nitrites; 

5.  Total  solids ; 

6.  Organic  and  volatile  matter  by  ignition  of  residue; 

7.  Oxygen  required  to  oxidize  organic  matter; 

8.  Color; 

9.  Carbonic  acid  (seldom  required)  ; 

10.  Dissolved  oxygen  (seldom  required). 

J  Consult:  "  Some  Recent  Methods  of  Technical  Water  Analysis,"  by  Prof.  H.  R. 
Procter.  /.  Soc.  Cheni.  Ind.,  January  12,  1904,  pp.  8-1 1  (relates  to  the  several  methods  of 
determination  of  hardness  in  water). 


EJNGINEERING   CHEMISTRY  589 

1.   Determination  of  Chlorine.    Standard  Silver  Solution. 

Dissolve  5  grams  of  pure  crystallized  silver  nitrate  in  distilled 
water  and  dilute  to  i  liter.  One  cc.  of  the  solution  is  equivalent 
to  o.ooi  gram  chlorine.  If  the  water  to  be  tested  shows  by 
qualitative  analysis  a  small  amount  of  chloride  present,  250  cc. 
of  the  water  should  be  evaporated  to  about  50  cc,  allowed  to 
cool,  three  drops  of  a  saturated  solution  of  potassium  chromate 
added,  and  the  silver  nitrate  solution  dropped  carefully  from  a 
burette  until  a  faint  permanent  red  color  is  produced  in  the  water. 
This  point  indicates  that  all  the  chlorine  has  combined  with  the 
silver,  and  that  any  additional  silver  solution  added  forms  silver 
chromate.    Thus : 

250  cc.  of  the  water  used  for  examination. 

250  cc.  of  the  water  required  1.3  cc,  silver  nitrate  solution. 

1,000  cc.  of  the  water  required  5.2  cc.  silver  nitrate  solution. 

Equivalent  to  0.0052  gram  of  chlorine  per  liter. 

Equivalent  to  0.52  part  chlorine  in  100,000  parts  of  the  water. 

Equivalent  to  5.20  parts  chlorine  in  1,000,000  parts  of  the  water. 

The  amount  of  chlorine  allowable  in  good  drinking-water  can 
not  be  stated  positively,  since  the  source  from  which  it  is  derived 
must  be  taken  into  account. 

Results  from  a  great  many  analyses  of  various  waters  would 
indicate  the  amount  allowed  as  follows : 

Rain  water Traces  to  i  part  per  1,000,000. 

Surface  water i  to  10  parts  per  1,000,000. 

Subsoil 2  to  12  parts  per  1,000,000. 

Deep  well  water Traces  to  large  quantity. 

2.   Free  and  Albuminoid  Ammonia. 

The  solutions  required  are: 

a.  Standard  solution  of  ammonium  chloride,  made  by  dissolving 
0.382  gram  dry  ammonium  chloride  in  100  cc.  of  ammonia-free 
distilled  water.  One  cc.  of  this  solution  is  diluted  to  100  cc.  with 
distilled  water,  each  cubic  centimeter  of  the  latter  solution  corre- 
sponding to  0.000012  gram  ammonia. 

h.  Standard  Nessler  Reagent. — Dissolve  17  grams  of  mercuric 
chloride  (pulverized)  in  300  cc.  of  water,  and  35  grams  of  potas- 


590  ENGINEERING   CHEMISTRY 

slum  iodide  in  lOO  cc.  of  water.  Pour  the  mercuric  chloride  so- 
lution into  the  potassium  iodide  until  a  permanent  red  precipi- 
tate is  formed.  Add  a  20  per  cent,  solution  of  sodium  hydroxide 
until  the  volume  of  the  mixed  solution  amounts  to  one  liter.  Add 
some  more  mercuric  chloride  solution  until  a  permanent  red  pre- 
cipitate forms  and  allow  to  settle. 

c.  Alkaline  potassium  permanganate,  formed  by  dissolving  eight 
grams  of  potassium  permanganate  and  200  grains  of  potassium 
hydroxide  in  a  liter  of  distilled  water. 

This  solution  is  concentrated  by  boiling  to  about  750  cc,  then 
250  cc.  of  ammonia-free  water  is  added.  When  properly  pre- 
pared this  solution  gives  but  traces  of  ammonia  by  distillation. 
In  any  event,  however,  it  must  be  tested,  and  if  an  appreciable 
amount  is  found,  it  must  be  deducted  from  the  determination  of 
albuminoid  ammonia  in  any  sample  of  water  under  examination. 

Ammonia-free  water  is  made  by  distilling  water  acidulated 
with  sulphuric  acid. 

Process. — The  apparatus  shown  in  Fig  105  is  well  adapted  for 
this  purpose. 

Place  250  cc.  of  the  water  to  be  tested  in  a  flask,  capacity  one 
liter,  add  i  cc.  saturated  solution  sodium  carbonate,  connect  with 
the  condenser  and  distil  until  no  reaction  for  ammonia  is  shown 
in  the  distillate  (caught  in  one  of  the  comparison  tubes) ^  when 
2  cc.  of  the  Nessler  solution  are  added  thereto,  a  yellowish  brown 
color  being  indicative  of  ammonia.  The  apparatus  being  free 
from  ammonia,  500  cc.  of  the  water  are  now  added  to  the  water 
remaining  in  the  flask  and  i  cc.  of  the  saturated  sodium  carbonate 
solution  (free  from  ammonia)  added.  Distillation  proceeds  un- 
til three  distillates,  each  of  50  cc,  have  been  received  in  the 
comparison  tubes,  when  the  distillation  is  stopped  and  the  heat  re- 
moved until  the  distillates  can  be  examined.  The  comparison 
tubes  are  protected  by  being  enclosed  in  a  glass  vessel,  with  a 
movable  top,  as  shown  in  Fig.  105,  at  the  base  of  which  is  an 
opening  filled  with  cotton  wool. 

1  vSee  Fig.  105. 


e:ngine:e;ring  chemistry 


591 


These  comparator  tubes  have  a  mark  indicating  50  cc,  and 
when  the  distillate  reaches  that  mark,  the  handle  of  the  stand 


containing  the  comparator  tubes  is  turned  and  another  compara- 
tor tube  placed  under  the  outlet  of  the  condenser.    The  revolving 


592 


EJNGINEJERING   CHEMISTRY 


stand  contains  seven  comparator  tubes,  sufficient  for  both  the 
free  and  albuminoid  ammonia  determinators.  C.  H.  Wolff's 
calorimeter  (Fig.  io6)  has  an  extended  use  in  water  analysis  for 
the  purpose  of  comparing  tints  of  color  of  the  water,  also  in  the 
determination  of  the  difference  in  color  in  the  estimation  of  free 
and  albuminoid  ammonia. 


<o 


=^ 


Fig.  io6. 


One  of  the  tubes  contains  the  nesslerized  standard  ammonium 
chloride  solution,  the  other  tube  a  portion  of  the  water  distillate, 
nesslerized,  to  compare  with  the  former.  The  contents  of  the 
tube  containing  the  darker  liquid  are  partially  drawn  off  by 
means  of  the  glass  stop-cock  at  the  base,  and  the  remaining 
liquid  diluted  with  distilled  water  until  a  uniform  tint  of  color 
is  obtained  in  both  glasses.  As  these  tubes  are  graduated,  the 
calculations  are  simplified  and  rendered  more  expeditious. 


DNGINKB^RING   CHEMISTRY  593 

Ammonia  Determinations. — The  first  50  cc.  of  distillate  are 
now  tested  for  ammonia,  as  follows : 

The  tube  is  removed  and  placed  in  a  comparator  and  2  cc.  of 
the  Nessler  solution  added.  The  color  produced  must  be  matched 
by  taking  another  tube  and  filling  to  the  50  cc.  mark  with  am- 
monia-free distilled  water,  adding  i  cc.  of  the  standard  ammon- 
ium chloride  solution  and  2  cc.  Nessler  solution.  Allow  to  stand 
five  minutes  for  full  development  of  color,  then  compare  the 
color  of  the  liquids  in  the  tubes. 

If  the  solution  containing  the  ammonium  chloride  is  too  strong, 
divide  it  and  add  distilled  ammonia- free  water  to  50  cc.  mark, 
and  compare  again ;  repeat  until  the  tints  are  identical. 

If,  however,  the  solution  containing  the  ammonium  chloride 
is  not  deep  enough  in  color,  add  more  of  the  standard  ammo- 
nium chloride  solution  and  compare  as  before. 

The  second  and  third  distillates  are  treated  in  a  similar  manner, 
but  if  the  third  distillate  shows  over  a  trace  of  ammonia,  a  fourth 
distillate  must  be  taken,  or  until  no  appreciable  amount  of  free 
ammonia  can  be  obtained. 
Free  Ammonia— 

500  cc.  of  the  water  taken. 

First  distillate  (50  cc.)  required  1.5  cc.  ammonium  chloride  solution. 
Second    "         (50  cc.)  "        0.3  cc.  "  "  " 

Third      "  (50  cc.)  "        none  "  "  " 


Total  for     500  cc.  1.8  cc. 

"         "    1,000  cc.  3.6  cc.  "  "  " 

One  cc.  ammonium  chloride  solution  is  equivalent  to  o.ooooi  gram 

nitrogen  or  0.000012  gram  of  ammonia. 
Then  one  liter  of  the  water  contains  0.000043  gram  free  ammonia. 
Equivalent  to  0.0043  part  aminonia  per  100,000. 
Equivalent  to  0.043  part  ammonia  per  1,000,000. 

Albuminoid  Ammonia. — Fifty  cc.  of  the  alkaline  solution  of  po- 
tassium permanganate  are  added  to  the  contents  of  the  flask,  after 
the  determination  of  the  free  ammonia.  The  contents  of  the  flask 
must  be  cooled  somewhat  before  the  addition  of  the  alkaline 
permanganate  solution.  The  latter  is  placed  in  the  flask  by  means 
of  the  glass  delivery  tube,  which  passes  through  and  is  fused 
to  the  glass  stopper  of  the  flask.  By  this  arrangement  any  solu- 
38 


594  e;ngineering  chemistry 

tion  can  be  added  to  the  contents  of  the  flask  without  removing 
the  stopper. 

The  distillation  and  comparison  of  distillates  by  known  amounts 
of  ammonium  chloride  solution  are  made  in  the  same  manner  as 
for  the  determination  of  free  ammonia. 

750  cc.  of  the  water  taken. 

First  distillate  required  3.2  cc.  ammonium  chloride  solution. 

Second     "  "  0.7  cc.  "  "  " 

Total  "  3.9  cc. 

1,000  cc.  "  5.2  cc.  "  "  " 

Equivalent  to  0.000062  gram  ammonia  per  liter. 
Equivalent  to  0.0062  part  ammonia  per  100,000  parts. 
Equivalent  to  0.0620  part  ammonia  per  1,000,000  parts. 

It  must  be  remembered  that  the  free  ammonia  was  determined 
in  the  500  cc.  of  water  after  the  free  ammonia  was  expelled 
from  the  250  cc.  of  water  first  placed  in  the  flask. 

As  the  albuminoid  ammonia  is  not  developed  until  the  addition 
of  the  alkaline  permanganate  solution,  the  determination  of  the 
albuminoid  ammonia  would  be  upon  750  cc.  of  the  water. 

The  amount  of  free  ammonia  in  potable  river  water  should  not 
exceed  0.120  part  per  million,  and  the  albuminoid  ammonia  0.280 
part  per  million.^ 

3.   Determination  of  Nitrates  by  the  Phenol  Method. 

a.  Standard  potassium  nitrate  solution,  formed  by  dissolving 
0.722  gram  potassium  nitrate,  C.  P.,  in  a  liter  of  water.  One  cc. 
of  this  solution  is  equivalent  to  0.00044  NO3. 

b.  P hen olsul phonic  acid,  formed  by  adding  together  3  cc.  of 
water,  6  grams  of  pure  phenol,  and  37  cc.  of  concentrated  sul- 
phuric acid. 

The  operation  of  determining  the  nitrates  is  as  follows : 
Twenty-five  cc.  of  the  water  are  evaporated  to  dryness  in  a 
No.  2  porcelain  capsule,  on  a  water-bath.     One  cc.  of  the  phe- 
nolsulphonic  acid  is  added  and  incorporated  thoroughly  with  the 
residue. 

Add  I  cc.  of  water,  3  drops  of  concentrated  sulphuric  acid, 

1  A.  R.  Leeds,  Ph.  D. 


ENGINEERING    CHEMISTRY  595 

and  warm.  Dilute  with  25  cc.  water,  make  alkaline  with  ammo- 
nium hydroxide  and  make  solution  up  to  100  cc.  with  water. 
If  an  appreciable  amount  of  nitrate  be  present,  it  forms  picric 
acid  with  the  phenol suphonic  acid,  imparting  a  yellow  color  to 
the  solution,  w^hen  the  ammonia  is  added  by  the  formation  of 
ammonium  picrate.  The  intensity  of  the  color  is  proportional  to 
the  amount  of  ammonium  picrate  present. 

One  cc.  of  the  standard  potassium  nitrate  solution  is  evaporated 
in  a  porcelain  capsule,  treated  as  above,  and  the  solution  made  up 
to  100  cc.  The  two  solutions  are  placed  in  comparator  glass  tubes 
and  distilled  water  added  to  one  or  the  other  until  the  colors 
agree  in  tint.  Suppose  25  cc.  of  the  original  water  after  treat- 
ment and  subsequent  dilution  to  100  cc.  corresponded  in  color  to 
the  standard  solution  of  i  cc,  which  after  treatment  and  dilution 
to  100  cc.  was  diluted  to  200  cc.  Then  25  cc.  of  the  original 
water  contained  0.00005  gram  nitrogen,  or  1,000  cc.  contained 
0.0020  gram  nitrogen  or  0.009  gram  NO3  per  liter,  corresponding 
to  0.52  grain  per  gallon,  or  0.9  part  per  100,000  or  9  parts  per 
1,000,000. 

The  amount  of  nitrates  in  American  river  water  should  not 
exceed  4  parts  per  million. 

4.   Nitrites. 

The  solutions  required  are : 

1.  Sulphanilic  Acid. — Dissolve  i  gram  in  300  cc.  of  acetic  acid 
(sp.gr.  1.04). 

2.  Sodium  Nitrate. — Formed  by  dissolving  0.272  gram  silver 
nitrate  in  100  cc.  water,  adding  a  dilute  solution  of  sodium  chlo- 
ride in  slight  excess,  and  diluting  to  250  cc. 

Take  100  cc.  of  this  solution,  dilute  to  i  liter  with  distilled 
water  for  use.     One  cc.  =  o.ooooi  gram  nitrogen. 

3.  a-Amidonaphthalene  Acetate. — Two-tenths  gram  of  naph- 
thylamine  is  boiled  with  40  cc.  of  water,  filtered  and  diluted  to 
400  cc.  with  dilute  acetic  acid. 

Pror^^^.- -Twenty-five  cc.  of  water  are  taken  and  placed  in 
one  of  the  color  comparators,  2  cc.  of  the  sulphanilic  acid  and  2 
cc.  of  the  amidonaphthalene  acetate  are  added.     If  nitrates  are 


596  ENGINEERING   CHEMISTRY 

present,  a  pink  color  is  produced,  which  must  be  compared  with 

the  color  produced  by  i  cc.  of  the  standard  nitrite  solution,  to 

which  2  cc.  of  the  sulphanilic  acid,  2  cc.  of  the  amidonaphthalene 

acetate,  and  25  cc.  of  pure  distilled  water   (free  from  nitrites) 

are  added.     This  comparison  should  not  be  made    until    after 

fifteen  minutes  interval. 

Suppose  25  cc.  of  the  water  required  0.6  cc.  of  the  standard 

nitrate  solution,  equivalent  to  0.000006  gram  nitrogen,  or  0.00002 

gram  NO2. 

Corresponding  to  0.0008  gram  NO2  per  liter. 
Corresponding  to  0.0800  part  per  100,000. 
Corresponding  to  0.8000  part  per  1,000,000. 

Nitrites,  if  found  in  river  water,  above  0.003  part  per  mil- 
lion, condemn  the  water  for  potable  purposes.  Regarding  their 
presence  in  deep  well  water  and  spring  water,  Frankland  says : 
"The  presence  of  these  salts  in  spring  and  deep  well  water  is 
absolutely  without  significance." 

Reference. 

"Notes  upon  the  Determination  of  Nitrites  in  Potable  Water,"  by  A.  H. 
Gill  and  H.  A.  Richardson,  /.  Am.  Chein.  Soc,  18,  21. 

5.  Total  Solids. 

The  total  solids  are  determined  by  evaporating  500  cc.  of  the 
water  in  a  platinum  dish  and  drying  the  residue  at  105°  C.  to 
constant  weight.  The  amount  obtained  multiplied  by  2  equals 
the  weight  per  liter. 

6.   Organic  and  Volatile  Matter. 

The  organic  and  volatile  matter  is  approximately  determined 
by  igniting  the  weighed  residue  until  all  carbonaceous  matter  is 
consumed,  and  weighing;  the  difference  between  the  weight  of 
the  total  solids  and  the  weight  after  ignition  is  the  organic  and 
volatile  matter.^ 

7.   Oxygen  Required  to  Oxidize  the  Organic  Matter  in  the  Water.^ 

Solutions  required : 

Standard    Potassium    Permanganate,    formed    by    dissolving 

1  As  a  portion  of  this  volatile  matter  may  be  COo  expelled  by  heating,  this  can  be  ob- 
tained again  by  placing  the  evaporating  dish  and  heated  solids  in  an  atmosphere  of  CO2 
until  the  required  COo  is  absorbed;  then  weigh,  the  loss  will  represent  the  organic 
matter. 

2  "Chemical  Examination  of  Water."     By  W.  P.  Mason,  p.  75. 


.  e;ngine;e:ring  chemistry  597 

0.395  gram  potassium  permanganate  in  1,000  cc.  water.     Each 
cubic  centimeter  contains  0.000 1  gram  available  oxygen. 

Dilute  Sulphuric  Acid  Solution. — One  part  by  volume  of  pure 
sulphuric  acid  is  mixed  with  three  parts  by  volume  of  distilled 
water  and  solution  of  potassium  permanganate  dropped  in  until 
the  whole  retains  a  very  faint  pink  tint,  after  warming  to  80°  F. 
for  4  hours. 

Solution  of  Oxalic  Acid. — 0.7875  gram  of  the  crystallized  salt 
in  1,000  cc.  distilled  water. 

This  solution,  if  titrated  against  the  permanganate  solution 
(while  hot,  and  in  presence  of  sulphuric  acid),  should  corre- 
spond to  it,  cubic  centimeter  for  cubic  centimeter.  In  practice, 
however,  this  will  be  found  approximate  only.  The  solution 
tends  to  grow  weaker  quite  rapidly  with  lapse  of  time,  and  must 
be  restandardized  every  time  it  is  used,  which  is  accomplished 
as  follows: 

Ten  cc.  of  the  oxalic  acid  solution,  diluted  with  200  cc.  pure 
water  and  10  cc.  of  the  dilute  sulphuric  acid,  are  titrated,  boil- 
ing, with  the  standard  potassium  permanaganate  solution,  and  the 
amount  of  the  latter  required  to  produce  a  faint  pink  tinge.,  is 
recorded. 

Determination. — Place  in  a  porcelain  dish  200  cc.  of  the  water 
under  examination,  and  add  10  cc.  of  the  dilute  sulphuric  acid. 
Heat  rapidly  to  incipient  boiling  and  run  in  the  standard  per- 
manganate solution  from  a  burette  until  the  water  has  a  very 
marked  red  color.  Boil  ten  minutes,  adding  more  permanganate 
from  the  burette  from  time  to  time,  if  necessary,  in  order  to 
maintain  the  intensity  of  red  color  observed  at  the  start.  Do 
not  let  the  color  fade  nearly  out,  and  then  add  the  permanganate 
in  quantity  at  once,  but  strive  to  keep  the  color  as  nearly  con- 
stant as  possible  by  gradual  addition. 

Remove  the  lamp,  add  10  cc.  (or  more,  if  necessary)  of  the 
oxalic  acid  solution  to  destroy  the  color,  and  then  add  the  per- 


598  ENGINEERING   CHEMISTRY 

manganate  solution  from  the  burette  until  a  faint  pink  tinge  again 
appears.  From  the  total  permanganate  used  deduct  that  corre- 
sponding to  the  10  cc.  (or  more)  oxalic  acid  employed,  and  from 
the  remainder  calculate  the  milligrams  of  ''required  oxygen" 
consumed  by  the  organic  matter  present  in  the  water.  Correc- 
tion must  be  made  for  nitrites,  ferrous  salt,  or  hydrogen  sul- 
phide if  any  of  them  be  present. 

Example : 

cc. 

Total  permanganate  solution  used 25.0 

Less  that  required  for  the  oxalic  acid  9.7 

Hence  that  required  to  oxidize  organic  matter   15.3 

corresponding  to  1.53  milHgrams  oxygen. 
Therefore,  "required  oxygen"  is  1.53  X  5  =  765  parts  per  million. 
Leed's  standard  for  American  rivers  =  5  to  7  parts  per  miL  on. 

8.   Color. 

The  color  of  water  is  to  be  considered  as  that  produced  by  sub- 
stances in  solution  and  not  by  substances  held  in  suspension. 

The  amount  of  color  is  generally  determined  by  a  comparison 
with  a  standard  platinum-cobalt  solution — for  complete  descrip- 
tion consult : 

"Standard  Methods  of  Water  Analysis."  (American  Public  Health 
Association,   1905),  pp.  20-23. 

"Standard  Prisms  in  Water  Analysis  and  the  Valuation  of  Color  in 
Potable  Waters."     /.  Am.  Chem.  Soc.,  18,  484. 

"The  Measurement  of  Colors  in  Natural  Waters."  /.  Am.  Chem.  Soc., 
18,  264. 

"The  Coloring  Matter  of  Natural  Waters,  its  Source,  Composition, 
and  Quantitive  Measurement."    /.  Am.  Chem.  Soc.,  18,  16. 

9.   Dissolved  Oxygen. 

The  method  devised  by  M.  Albert  Levy,  of  the  Montsouris 
Observatory,  Paris,  is  to  be  recommended.     For  this  consult: 
"Water  Supply,"  W.  P.  Mason,  pp.  413-4^0. 

10.   Carbonic  Acid* 

Carbonic  acid  is  seldom  determined  in  a  sanitary  analyses  of 
water.     It  generally  exists  in  three  forms,  fixed,  half  combined 


ENGINEERING   CHEMISTRY 


599 


For  a  comparison  of  the  methods  of  determination, 


by  F.  B. 


and  free, 
consult : 

"The  Determination  of  Carbonic  Acid  in  Drinking  Water, 
Forbes  and  G.  H.  Pratt.    /.  Am.  Chem.  Soc,  1904,  pp.  742-756. 

Conversion  Table. 

Parts  per      100,000  X  0.7  =  Grains  per  Imperial  gallon, 

Parts  per  1,000,000  X  0.07  =  Grains  per  Imperial  gallon. 

Parts  per      100,000  X  0.583  =  Grains  per  U.  S.  gallon. 

Parts  per  1,000,000  X  0.058  =  Grains  per  U.  S.  gallon. 

Parts  per  i,ooo,oocj  X  0.00833  =  Avoir,  pounds  per  1,000  U. 

Grains  per  Imp.  gal.  -^   0.7  Parts  per      100,000. 

Grains  per  Imp.  gal.  -^  0.07  Parts  per  1,000,000. 

Grains  per  U.  vS.  gal.  -^  0.583  Parts  per      100,000. 

Grains  per  U.  S.  gal.  H-  0.058  Parts  per  1,000,000. 


S.  gal. 


CERTIFICATE  OF  WATER  ANALYSIS. 

From  whom  received  No. 

When  received   Title  of  Label 

Source  of  Sample   

COLOR TASTE ODOR 


I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VIII. 

IX. 

X. 

XI. 

XII. 

XIII. 


DATA  OBTAINED  BY  ANALYSIS: 


Parts  in  1,000,000 


Grains  per  Gallon 


Free  Ammonia   

Albuminoid  Ammonia 

Oxj^gen    Required    to    Oxidize 

Organic  matter   

Nitrogen  in  Nitrites   

Nitrogen  in  Nitrates    

Chlorine   

Total  Hardness    

Permanent  Hardness    

Temporary  Plardness   

Total   Solids 

Mineral   Matter    

Organic  and  Volatile  Matter  . . 
Other  data,  when  required   for 

judgment 


INTERPRETATION  OF  RESULTS  OF  ANALYSIS: 


Signed. 


600  I^NGINEJ^RING   CHEMISTRY 

BACTERIOLOGICAL  EXAMINATION  OF  WATER. 

The  following  references  are  given : 

"The  Microscopy  of  Drinking  Water,"  by  G.  C.  Whipple,  N.  Y,,  1904. 
"Standard   Methods   of  Water  Analysis,"    (American  Public  Health 
Association,  1905). 


FILTRATION  OF  WATER. 

Filtration  of  water  for  the  supply  of  towns  and  cities  is  per- 
formed either  by  sand  filter-beds — the  English  system,  or  by 
mechanical  filters — the  American  system.  Both  processes  are 
used  in  this  country. 

The  following  references  are  given : 

"Water  Supply,  Considered  Principally  from  a  Sanitary  Standpoint," 
by  W.  P.  Mason,  N.  Y.,  1904. 

"PubHc  Water  Supplies:  Requirements,  Resources,  and  the  Construc- 
tion of  Works,"  by  F.  E.  Turneaure  and  H.  L.  Russell,  N.  Y.,  1901. 

"The  Purification  of  Public  Water  Supplies,"  by  Allen  Hazen,  N.  Y., 
1901. 

Use  of  Chemicals  with  Filtration  of  Water. 

Dervaux  Water  Purifier  for  Boiler  Use. 
The  apparatus  (Figs.  107,  108)  is  automatic  in  action  and  is 
thus  described.  The  purifier  is  intended  to  act  as  an  eliminator 
for  both  calcium  sulphate  and  calcium  and  magnesium  carbo- 
nates. It  not  only  acts  to  precipitate  the  dissolved  impurities,  but 
also  to  collect  those  that  are  in  suspension.  These  last  are  caught 
and  held  in  the  tower-shaped  holder  D.  The  water  enters  at 
H,  passes  down  through  B,  and  is  made  to  rise  through  a  series 
of  funnels  or  inclined  funnel-shaped  walls.  On  these  walls^  the 
coarsest  particles  are  caught  and  from  them  they  flow  down  to 
the  bottom  of  the  tower,  where  they  collect;  the  water  then 
passes  upward  though  the  filters  F,  which  are  made  of  wood 
shavings,  and  flows  oft",  freed  from  its  mechanical  impurities 
through  the  opening  T.  In  the  meantime,  by  the  addition  of  lime 
and  soda,  the  water  has  been  chemically  purified  in  the  following 
way:  The  water  first  flows  through  the  reservoir  C,  through 
the  pipe  //.     In  C,  there  is  a  float  for  regulating   the    flow    of 

1  "The  Chemistry  of  Paper-making,"  p.  335. 


Kngine;e:ring  chejmistry 


60 1 


water.    A  portion  of  the  water  goes  through  B,  through  the  pipe 
P,  while  the  rest    passes    through    the    valve  V  into    the    lime 


Fig.  107.  Fig.  108. 

saturator  S;  S  is  filled  with  lime;  the  water  first  meets  the  lime 
at  the  bottom  of  the  saturator  and  passes  up  through  it;  the 
conical  shape  of  S  causes  the  rise  to  be  slower  and  slower  as 


602  ENGINPJIJRING   CHEMISTRY 

the  water  nears  the  top,  so  that  the  milk  of  lime,  at  first  formed, 
has  plenty  of  time  to  clarify  itself.  The  lime-water  usually  con- 
tains some  calcium  carbonate  in  suspension :  and  as  this  is 
w^orthless  for  purposes  of  purification,  it  is  eliminated  by  causing 
the  water  to  flow  over  into  the  cone  K,  which  is  closed  at  the 
bottom.  In  this  cone  the  carbonate  settles  out,  and  may  be 
drawn  off  through  G.  The  clear,  saturated  lime-water,  contain- 
ing 1.3  grams  of  lime  per  liter,  runs  then  directly  into  the  mixing 
tube  B.  A  solution  of  soda-ash  is  made  by  taking  a  known 
weight  of  the  ash,  which  is  placed  in  the  tank  Z,  after  which  the 
tank  K  is  filled  to  a  definite  mark  with  water.  This  solution 
slowly  passes  through  the  tube  provided  with  strainers :  a  float 
in  the  tube  keeps  the  water  in  B  at  constant  level.  The  siphon 
A^,  one  end  of  which  dips  to  the  bottom  of  B,  allows  the  alkaline 
solution  to  flow  into  B.  The  regulation  of  the  flow  in  B  is  per- 
formed as  follows :  The  siphon  A^  is  joined  by  a  chain  Q,  to  the 
float  in  C.  In  case  the  flow  of  water  through  //  to  C  is  cut  off, 
the  float  sinks,  raising  N  and  thus  stopping  the  flow  of  the  solu- 
tion. At  the  same  time  the  level  in  C  sinks  so  low  that  the  flow 
of  water  through  P  and  V  ceases;  as  soon  as  the  flow  of  water 
through  H  recommences,  the  apparatus  is  again  set  in  operation 
automatically. 

The  chemical  operations  may  be  stated  as  follows :  The  addi- 
tion of  the  lime  softens  the  water  by  precipitating  any  bicar- 
bonate which  may  be  present,  and  the  excess  of  lime  is  thrown 
down  by  the  sodium  carbonate.  This,  by  its  precipitation,  throws 
out  much  of  the  finely  divided  organic  impurity.  The  apparatus 
may  be  easily  modified  to  work  with  alum  where  desirable. 

This  Dervaux  Purifier  is  extensively  used  in  France  and  Ger- 
many. 

References. 

"Industrial  Uses  of  Water,"  by  H.  De  la  Coux,  Professor  of  Applied 
Chemistry  and  Expert  to  the  Perfecture  of  the  Seine,  etc.  Trans- 
lated from  the  French  by  Arthur  Morris,  New  York,  1903. 

"Water  and  Its  Purification,"  a  handbook  for  the  use  of  local  authorities, 
sanitary  officers,  and  others  interested  in  water  supply,  by  Samuel 
Rideols,  London,  1902. 


ENGIN^I^RING    CHHJMISTRY 


603 


Filter-presses  are  often  used  for  rapid  filtration  of  water.  These 
presses  consist  of  a  number  of  filter  chambers  with  solid  sepa- 
rating walls,  which  are  held  between  two  head  pieces,  one  of 
which  is  fast  and  the  other  movable;  the  latter  as  well  as  the 
filtering  frames  slide  along  two  strong  iron  rods.  Between  the 
chambers  the  filtering  cloth  is  hung  and  this  also  helps  to  make 
the  outer  edge  fit  closer  together.  The  whole  system  is  pressed 
together  by  a  screw  or  lever  or  by  hydraulic  pressure  and  forms 
a  number  of  hollow  spaces  lying  together  and  communicating 


Fig.  109.-25-111.  square  filter- press  with  electrically  driven  pump. 
(Mfg.  by  vS.  H.  Johnson  &  Co.   lyondon,  Eng.) 

with  one  another.  Between  these  hollow  spaces  the  liquid  to  be 
filtered  is  pressed  by  a  pump  or  other  means.  During  this  pro- 
cess the  separation  of  the  liquid  and  solids  takes  place,  in  that  the 
liquid  is  forced  through  the  cloth  and  runs  out  clear  through 
channels  to  a  common  outlet,  leaving  the  solids  behind. 

We  distinguish  two  varieties  of  filter  presses : 

I.  Chamber  presses,  by  which  the  space  for  the  cake,  i.  e.,  the 


6o4 


ENGINEERING   CHEMISTRY 


solid  matter  remaining,  is  formed  by  the  edges  of  each  two  filter- 
plates,  so  that  the  cake  falls  out  when  the  press  is  opened. 

2.  Frame  presses,  by  which  the  space  for  the  cake  is  formed  by 
frames  that  are  placed  between  each  two  filter-plates,  so  that  the 
cake  can  be  lifted  out  with  the  frames. 

In  order  to  dry  the  cake  completely  and  to  wash  it,  when  nec- 
essary, there  are  in  most  filter-presses  two  extra  canals  in  each 
chamber,  one  in  which  the  washing  fluid  enters  and  the  other 
liquids  can  be  filtered  hot  or  cold. 


Fig.   no. 

The  Porter-Clark  process  for  softening  hard  water,  largely 
used  in  England,  often  makes  use  of  filter-presses  to  remove  the 
precipitated  material  in  the  water.  Where  this  latter  precipitate 
is  very  fine  and  small  in  amount,  manufacturing  establishments 
sometimes  arrange  a  system  as  shown  in  Fig.  no  in  which  fi- 
bers of  cellulose  are  added  to  collect  the  fine  precipitate.  The 
apparatus  consists  of  a  high  horizontal  reservoir,  H  (Fig.  no), 
for  reception  of  the  water  to  be  filtered,  another  reservoir  or 
tank,  M,  in  which  the  floating  material  (or  fibers  of  cellulose  or 
asbestos)  is  mixed  with  water,  a  reservoir,  R,  into  which  the 
purified  water  flows  and  the  filtering  apparatus  proper,  F.     The 


ENGINEERING   CHEMISTRY 


605 


latter  is  composed,  as  are  the  filter-presses,  of  a  series  of  frames 
on  which  metal  sieves  are  fastened.  The  filtration  takes  place 
in  the  following  manner :  The  thin  mass  of  cellulose  or  asbestos 
fibers  are  caught  by  the  sieves  and  remain  on  them;  the  water  is 
then  allowed  to  pass  from  the  reservoir  H,  through  he  sieves 
which  now  hold  back  all  suspended  matter,  so  that  clear  water 
flows  in  the  reservoir  R. 

Another  method  made  use  of  in  some  large  industrial  plants, 
is  to  combine  the  action  of  a  heater,  chemical  precipitation  and 
filtration  by  filter  presses  as  shown  in  Fig.  iii. 


Fig.  III. 

The  water  passes  first  through  the  heater  A,  in  which  it  is 
brought  to  the  temperature  of  the  heater,  thence  into  the  pre- 
cipitation tank  B,  in  which  it  is  mixed  with  the  chemicals  in  solu- 
tion, the  latter  being  pumped  into  B  from  F  by  means  of  the 
pump  D.  The  water  then  passes  into  the  filter-press  C,  in  the 
chambers  of  which  the  suspended  matter  is  retained,  and  is  then 
pumped  by  the  pump  B,  either  directly  to  the  boiler  or  else  to  a 
reservoir.  The  water  and  chemicals  are  mixed  in  the  proportions 
shown  to  be  necessary  by  analysis.  This  system  of  water  puri- 
fication has  shown  itself  to  be  very  successful,  but  the  filter-press 
must  be  cleaned  every  two  to  eight  days  according  to  the  com- 
position of  the  water. 


6o6  ENGINEERING    CHEMISTRY 

WATER  FOR  LOCOMOTIVE  USE. 

After  many  years  of  experiment  upon  waters  for  locomotives, 
by  the  chemists  of  the  Chicago,  Milwaukee  &  St.  Paul  R.  R., 
the  results  obtained  may  be  stated  as  follows : 

Varieties  of  water  may  be  classified  by  either  of  two  methods : 

1.  By  their  chemical  composition; 

2.  By  their  effect  in  use. 

The  second  is  manifestly  what  is  wanted  by  master  mechanics 
and  superintendents.  The  following  may  be  placed  in  the  first 
class : 

a.  Alkaline  waters; 

b.  Non-alkaline,  bad,  and  good. 
In  the  second  class   (2)  : 

a.  Those  causing  foaming  and  corrosion,  but  non-incrusting; 

b.  Hard,  or  incrusting; 

c.  Soft,  non-alkaline,  and  good. 

These  two  classes  are  related  as  follows : 

"a"  of  class  i,  "alkaline"  waters,  will  produce  the  trouble  men- 
tioned in  "a"  of  class  2;  that  is,  foaming  and  in  certain  cases 
corrosion. 

''b,"  the  bad  '*non-alkaline,"  would  be  classed  as  hard  or  in- 
crusting. 

''c,"  "soft  waters,"  would  include  all  those  having  little  min- 
eral impurities  of  any  kind. 

It  is,  however,  impossible  to  set  hard  and  fast  limits  for  each 
class,  one  generally  shading  into  the  other,  and  what  would  be 
called  good  water  in  the  west,  for  instance,  would  be  thought 
poor  enough  in  the  east. 

In  making  an  analysis  all  ingredients  are  grouped  broadly 
under  two  heads,  "incrusting"  and  "non-incrusting."  Under 
the  former  are  put  such  salts  as  are  thrown  out  of  solution  by 
heat,  and  in  the  latter  case  those  which  do  not  precipitate  until 
great  concentration  occurs — a  condition  which  hardly  ever  hap- 
pens with  locomotives. 


ENGINRBJRING    CHEMISTRY  607 

In  the  "non-incrusting"  group  is  found  a  variety  of  actions. 
A  well-known  property  of  alkali  in  water  is  to  cause  foaming  and 
priming,  when  sudden  reduction  of  pressure  occurs  upon  opening 
the  throttle.  At  just  what  point  this  action  begins  to  be  apparent 
depends  upon  a  number  of  circumstances.  When  a  boiler  is  over- 
worked and  foul  from  mud,  it  appears  sooner  than  in  one  having 
ample  heating  surface,  with  moderate  train  load,  uniform  resis- 
tance and  consequent  regular  consumption  of  steam.  For  a  max- 
imum allowable  with  good  results  in  service  and  in  the  west, 
where  really  good  water,  as  before  mentioned,  is  uncommon,  50 
grains  per  gallon  of  alkaline  water  are  taken.  When  this  figure 
is  exceeded  it  certainly  pays  to  institute  a  regular  search  for 
better  water.  With  these  non-incrusting  salts  are  associated  a 
few  that  are  readily  decomposed  in  contact  with  iron,  and  attack 
it,  causing  gradual  corrosion.  These  are  most  commonly  the 
magnesium  chlorides  and  sulphates,  a  very  small  amount  of 
which,  say  10  grains  per  gallon,  should  condemn  the  water.  Or- 
ganic matter  is  supposed  also  to  have  this  action,  but  in  the  pres- 
ence of  alkali  the  danger  is  not  great  and  with  frequent  blowing- 
out  little  attention  need  be  given  it.  The  waters  may  be  classi- 
fied as  follows : 

I  to  10  grains  of  solids  per  gallon,  soft  water. 

10  to  20  grains  of  solids  per  gallon,  moderately  hard  water. 

Above  25  grains  of  solids  per  gallon,  very  hard  water. 

On  this  railroad  ''boiler  compounds"  are  employed.  Waters 
having  35  to  40  grains  of  incrusting  matter  per  gallon  can  be 
dealt  with  successfully,  provided  no  alkali  he  present.  The  above 
reservation  is  made  because  the  ''compound"  is  itself  an  alkali; 
so  in  adding  it  to  a  water  care  must  be  taken  not  to  bring  the  total 
alkali  above,  say,  50  grains  per  gallon,  or  there  will  be  trouble 
from  foaming.  In  the  "Report  of  Analysis"  blanks,  directions 
are  given  fixing  the  amount  of  compound  to  use  in  each  case.^  A 
few  examples  of  the  different  kinds  of  water  used  on  this  road 
are  here  given,  illustrating  the  distinctions  above  drawn.     The 

^  This  compound  is  a  mixture  of  i  pound  of  caustic  soda  and  %  pound  of  sodium 
carbonate,  dissolved  in  i  gallon  of  water,  the  average  cost  of  a  run  of  i,ooo  miles  being 
about  40  cents. 


6o8  ENGINEERING   CHEMISTRY 

best  is  surface  water,  in  the  forest  region  of  Wisconsin;  for  ex- 
ample, that  from  Wausau,  as  follows : 

Grains  per  gallon 
Total  solid  residue 6.78 

i  Oxide  ot  iron 0.23 
Calcium  carbonate 2.20 
Calcium  sulphate 0.46 


Total 2.95 

Non-incrusting      (  Organic  and  volatile 3.15 

matter \  Alkaline  chlorides 0.68 


Total 3.83 

For  boiler  purposes  this  water  is  admirable,  the  incrusting  mat- 
ter, about  3  grains,  being  inappreciable. 

For  a  good  example  of  badly  incrusting  water,  but  non-alkaline, 
the  following  from  Lennox  Creek,  Dakota,  may  be  given : 

Grains  per  gallon 

Total  solid  residue •  ■    109.20 

T  .•  .,       f  Calcium  carbonate 40.31 

Incrusting  matter  |  Magnesium  carbonate 7.17 

Total 47.48 

-,       .  .    r  Organic  and  volatile 14.34 

Non-incrust-  I  Magnesium  sulphate 46.07 

ing  matter  j^  ^jkaline  chlorides 1.31 

Total 61.72 

This  water  could  not  be  properly  purified  by  the  addition  of 
caustic  or  carbonated  alkali  without  introducing  an  inadmissible 
amount  of  the  latter,  as  above  noted. 

It  will  be  noticed  that  the  magnesium  sulphate  is  classed  as 
"non-incrusting"  matter.  It  is,  however,  much  more  hurtful  than 
the  lime  salts  on  account  of  its  corrosive  properties.  The  organic 
matter  is  also  high,  but  not  more  so  than  is  usual  for  a  surface 
water  in  that  locality. 

All  the  roundhouses  are  provided  with  hydrants  and  high- 
pressure  steam  connections  for  the  purpose  of  obtaining  a  power- 
ful stream  of  hot  water  for  wash-out  use. 

On  eastern  divisions,  locomotives  having  run  from  1,500  to 
2,000  miles  are  blown  off  at  low  pressure,  cooled,  and  the  stream 
of  hot  water  thrown  in  at  hand-holes,  from  tube-sheet  and  back 


e;ngine:f,ri]ng  chemistry  609 

head,  and  scraper  worked  in  and  out.  The  sediment  is  found 
mostly  loose  and  in  the  form  of  fme  mud,  to  the  amount  of  10  to 
15  bucketfuls.  After  thorough  cleaning,  the  boiler  is  again  filled 
with  hot  water,  and  is  ready  for  service. 

On  the  western  divisions  the  frequency  of  washing  out  is  in- 
creased, doing  so  as  often  as  once  every  300  or  4CX)  miles  run. 
As  to  the  economy  of  using  hot  water  always,  there  can  be  no 
question.  Fully  75  per  cent,  in  the  number  of  cracked  fire-box 
sheets  are  saved  by  this  practice  alone,  and  it  materially  reduces 
the  force  of  repairers  in  roundhouses,  notwithstanding  a  very 
large  increase  of  engine  mileage. 

Many  people  are  opposed  to  the  use  of  chemicals  in  boilers, 
rightly  upon  general  principles ;  but  when  the  proper  ones  are 
used,  the  experiments  have  failed  to  show  the  slightest  injury 
therefrom,  while  the  economy  resulting,  both  in  service  and 
repairs,  has  amounted  to  an  enormous  sum  on  this  system. 

As  an  example  of  the  latest  development  in  the  purification  of 
railroad  water  supply  for  boiler  use,  the  following  description  of 
the  Kennicott  water-softening  plant  is  given  (Fig.  112). 

In  its  manner  of  working  it  resembles  the  Derveaux  water- 
softening  plant,  quite  largely  used  in  Europe,  p.  601.  The  soft- 
ener consists  of  a  cylindrical  steel  tank  Surmounted  by  a  platform 
upon  which  the  small  amount  of  housing  necessary  to  protect  the 
apparatus  from  the  weather  is  erected.  Surmounting  the  tank  is 
the  water  wheel  over  which  the  hard  water  is  first  pumped  on 
its  way  into  the  softener.  The  necessary  receptacles  for  dissolv- 
ing the  reagents  and  the  apparatus  for  automatically  varying  the 
reagents  in  proportion  to  the  amount  of  water  to  be  purified  are 
placed  upon  the  top  of  the  tank.  Centrally  located  within  the 
tank  is  the  conical  downtake  or  cone,  and  within  this  cone  is  the 
lime-water  saturator,  placed  in  this  position  in  order  to  protect 
the  miovable  stirrer  from  damage  by  freezing.  In  a  compartment 
in  the  top  of  the  lime  saturator  tank  is  the  mixing  chamber.  In 
this  chamber  the  water  and  the  necessary  reagents  for  its  puri- 
fication are  intimately  mixed,  so  that  the  precipitation  of  the 
scale-forming  material  at  once  takes  place.  The  water  with  the 
39 


6io 


ENGINEERING   CHEMISTRY 


precipitated  lime  and  magnesia  overflows  from  the  mixing  cham- 
ber and  travels  slowly  downward  through  the  downtake  or  cone. 
On  account  of  the  size  and  shape  of  this  downtake  the  rate  of 
flow  of  the  water  constantly  decreases,  so  that  the  precipitate 
falls  away  from  the  water  from  which  it  was  formed  and  collects 
in  the  conical  bottom  of  the  main  settling  tank,  where  it  is  peri- 
odically blown  out  into  the  sewer  by  means  of  a  dump  valve. 
Upon  reaching  the  bottom  of  the  cone  or  downtake  the  w^ater 
turns  and  rises  through  the  perforated  bafl^e  plates  and  the  small 


Fig.  112. 


amount  of  precipitate  left  in  the  water  attaches  itself  to  these 
plates ;  when  sufficient  precipitate  has  gathered  upon  the  plates 
it  slides  ofif  and  falls  to  the  bottom  of  the  tank.  These  plates 
never  need  to  be  cleaned.  The  water  finally  passes  through  the 
wood  fiber  filter,  at  the  top  of  the  apparatus,  where  the  last  par- 
ticles of  stispended  matter  are  removed  and  it  emerges  from  the 
top  of  the  softener  and  flows  through  the  overflow  pipe  soft  and 
clear,  and  is  discharged  into  the  storage  tank  without  repumping. 
The  chemicals  used  are  lime  and  soda-ash. 

The  following  report  shows  the  results  obtained  upon  boiler 
waters  on  the  Union  Pacific  Railroad  by  this  apparatus : 


ENGINEERING   CHEMISTRY 


6ll 


Report  oi-'  thk  Examination  of  the  Water  Suppi.y,  Kansas  Division 
OF  THE  Union  Pacific  Raieroad. 

(Made  at  the  Kennicott  I,aboratories) 


Stations 


Lawrence.    •• 

Topeka 

Wamego 

Junction  City 

Salina 

Ellsworth 

Dorrance 


CO 


bcA  . 
OJ  3  O 

>    U2^ 


300,000 
300,000 
200,000 
200,000 
300,000 
200,000 
200,000 


20 
20 
20 
20 
20 
20 
20 


1-  P  e 
o  '-'  5 


21.87 
32.86 
28.08 
18.72 
25.27 

18.79 
26.07 


1^  ^ 


3*..  D«*H 

h  O  >  a;  *J 

tn  tn  ii  tfl  » 

O   »3.Q.EI-M 


937.2 

1,408.2 
802.2 

534.8 

1,083.0 

536.8 
744.8 


Totals 1,700,000  gall< 


6,047.81b 


Average  cost  of  treatment  per  1,000  gallons,  1.8  cents. 


FEED-WATER  HEATERS. 

Feed-water  heaters  as  well  as  boiler  economizers  are  often  used 
as  eliminators  of  the  scale-forming  materials  in  water.  This  is 
due  to  the  fact  that  waters  containing  much  calcium  and  mag- 
nesium carbonates  when  heated  to  the  usual  temperature  in  feed- 
water  heaters  (20o°-2io°  F.),  give  up  the  excess  of  carbon  diox- 
ide that  holds  the  calcium  and  magnesium  carbonates  in  solution, 
and  the  latter  are  precipitated  and  removed  before  the .  water 
enters  the  boiler. 

Where  calcium  sulphate  is  a  large  constituent  of  the  water, 
feed-water  heaters  using  exhaust  steam  do  not  precipitate  the 
lime  salt,  but  if  the  feed-water  be  heated  by  live  steam  under 
pressure  to  a  temperature  of  240°  F.,  then  the  calcium  sulphate 
begins  to  precipitate.  The  addition  of  the  water  before  it  en- 
ters the  heater  of  the  necessary  amount  of  sodium  carbonate  will 
precipitate  the  lime  as  carbonate,  at  ordinary  temperatures  if 
several  hours  are  allowed  for  sedimentation,  or  if  heat  can  be 
used  the  chemical  action  will  be  hastened. 

An  example  of  an  upright  closed  feed-water  heater  heated  by 
exhaust  steam  is  the  "Goubert." 


6l2 


ENGINEERING    CHEMISTRY 


The  exhaust  steam  from  the  engine  is  admitted  to  the  shell 
through  the  nozzle  on  one  side,  and  spreading  between  the  brass 
tubes,  impinges  upon  them  on  its  passage  across  to  the  outlet  on 
the  opposite  side,  while  the  aggregate  area  of  the  spaces  between 


Fig.  113. — The  Goubert  closed  feed-water  heater,  vertical  type. 


the  tubes  is  so  much  better  than  that  of  the  exhaust  pipe  that 
no  obstruction  is  offered  to  the  flow  of  the  stream,  and  absolutely 
no  back  pressure  reverts  upon  the  engine. 

The  water  condensation  is  removed  by  the  drip  pipe,  which 


e;ngine;h;ring  chemistry  613 

should  be  kept  always  open,  and  it  is  a  peculiarity  of  the  con- 
struction of  this  heater  that  the  oil  or  grease  in  the  steam  is 
almost  entirely  removed  and  passes  off  with  the  drip,  leaving  the 
remainder  of  the  exhaust  free  from  contamination  and  avail- 
able for  other  purposes  for  which  live  steam  has  ordinarily  to 
be  used. 

The  cold  feed-water  enters  at  the  bottom  of  the  apparatus, 
is  spread  by  the  deflector,  and,  passing  under  the  edge  of  the  lat- 
ter in  a  thin  sheet,  allows  the  particles  of  mud  or  sediment  it 
carries  to  settle,  undisturbed,  in  the  bottom  of  the  water-chamber, 
there  being  no  heat  at  this  point,  and  consequently  no  circulation. 

The  water  then  flows  upward  through  the  tubes,  and  being 
divided  up  in  small  streams  becomes  heated  quickly ;  as  each  tube 
is  surrounded  by  steam  no  heat  is  lost  by  radiation  before  the 
water  leaves  the  heater,  a  result  that  some  makers  of  steam  tube 
heaters  have  endeavored  to  attain  by  surrounding  the  shell  with 
a  steam  jacket. 

The  construction  of  the  upper  water-chamber,  similar  to  that 
of  the  lower  one,  permits  the  rise  of  scum  to  the  top  and  its 
subsequent  removal  from  the  surface  below.  A  mud  blow-off 
pipe  is  also  provided  in  the  bottom  chamber. 

The  Goubert  Feed-Water  Heater  is  particularly  easy  to  clean. 
By  lifting  the  top  chamber  the  ends  of  all  the  tubes  are  exposed; 
a  swab  or  brush  may  then  be  used  to  clean  the  tubes.  This,  how- 
ever, needs  to  be  done  but  rarely,  and  if  the  surface  and  mud 
blows  be  open  for  a  few  seconds  ever3^-day,  the  heater  is  readily 
kept  clean  and  very  little  sediment  is  ever  found  to  adhere  to  the 
interior  surfaces  of  the  tubes. 

By  leaving  the  blow-off  valve  open  at  night,  or  when  not  in 
use,  the  heater  can  be  thoroughly  drained  to  avoid  the  danger  of 
freezing  in  cold  weather. 

The  various  forms  of  open  feed-water  heaters  are  worked  upon 
the  same  principle  of  collecting  the  scale- forming  material  from 
the  water  before  it  enters  the  boilers. 

A  sample  of  hard  water  was  submitted  to  the  writer  for 
analysis   and   from  the   analysis   to   determine   the   best   method 


6i4  Engine:e:ring  che:mistry 

of  treatment  for  purification  of  the  water  before  it  entered  the 
boilers.  The  analysis  of  the  residue,  dried  at  212°  F.,  of  the 
untreated  water  was  as  follows : 

Untreated  Water. 

Parts  per  Grains  per 

millon.  U.  S.  gallon 

Si02    12.  0.69 

SO3    65.  3.77 

CI    62.5  3.62 

NazO    53.1  3.07 

MgO  36.0  2.08 

CaO    122.  7.07 

AUOsFe^O.    6.6  0.38 

CO2  102.4  5.98 

Organic 20.4  1.18 

Total    480.  27.84 

Total  hardness  =  20.03°. 

T  lb,  12  ozs.  of  lime  (CaO)  80  per  cent.,  and  10  ozs.  of  soda 
ash,  (96  per  cent.)  were  used  for  each  1,000  gallons  of  the  water. 
After  allowing  the  chemicals  to  act  upon  the  water  12  hours  in 
settling  tanks,  the  water  passed  into  the  feed-water  heater.  Here 
more  precipitation  of  the  incrustating  solids  took  place,  showing 
that  even  long  sedimentation  under  cold  treatment  did  not  suffice 
to  reduce  sludge  and  scale  forming  solids  to  a  minimum.  An 
analysis  of  this  deposit  being  as  follows : 

Anai.ysis  oe  the  Deposit  prom  Heater. 

Per  cent. 

Moisture   (212°  F.)    3.14 

Water  of  hydration   15.92 

Oir    10.34 

Organic  matter   4.15 

CO. 12.01 

SiO.    15.93 

CaO   19.34 

MgO  18.60 

AloOs.FcaOs    0.48 

Undetermined    0.09 

Total   100.00 

^  From  condensed  steam  returned  to  heater — showing  that  if  any  oil-separator  was 
used  it  was  not  effective. 


ENGINEERING   CHEMISTRY 


615 


AXAI.YS1S  OF  Treated  Water,  After  Passing  the  Heater. 

Parts  per  Grains  per 

million  U.  S.  gallon 

SiOs    9.  0.52 

SO3    64.6  3.74 

CI 62.5  3.62 

Na^O    136.5  7.91 

MgO    16.9  0.99 

CaO    19.3  I. II 

Al2O3.Fe.O3  2.6  0.15 

CO2  59.9  3.49 

Organic 9.7  0.56 

Total   381.  22.09 

Total  hardness  —  3.4°. 

Thus  it  will  be  seen  that  the  amount  of  scale-forming  material 
in  the  untreated  water  (20°)  is  reduced  to  3.4°  in  the  water  as 
it  enters  the  boilers — (soft  water).  Much  better  results  are  fre- 
quent. 

Independent  of  the  fact  that  feed-water  heaters  are  more  or 
less  removers  of  scale-forming  materials,  in  the  original  water, 
they  also  act  as  fuel  economizers. 

In  the  above  sample  the  water  was  purified  by  use  of  chemicals 
and  sedimentation  in  tanks  before  passing  into  the  feed-water 
heaters.  Improvements  have  been  made  which  can  best  be  shown 
by  a  description  of  one  of  these  methods — the  Sorge-Cochrane 
hot  process  feed-water  softener. 

This  process  of  softening  of  water  for  boiler  use,  may  be  re- 
garded as  an  extension  of  the  Cochrane  feed-water  heater,  in 
which  water  sprayed  over  a  series  of  baffle  plates  is  heated  by 
immediate  contact  with  the  exhaust  steam,  the  latter  having 
previously  been  purified  of  oil  by  passing  through  an  oil  sep- 
arator attached  to  and  forming  a  part  of  the  heater  (Fig.  115). 

The  temperature  obtained  in  the  heater  (210°  F.,  or  higher, 
depending  upon  the  back  pressure),  has  the  effect  of  driving 
out  air  or  other  gases  from  the  water,  such  as  carbon  dioxide, 
including  carbon  dioxide  in  combination  as  well  as  in  solution. 
In  the  case  of  water  containing  salts  of  lime,  this  results  in  the 
changing  of  the  soluble  bi-carbonates  to  the  insoluble   normal 


6i6 


ENGINEERING   CHEMISTRY 


Fig.  114.— Represents  an  interior  view  of  a  Cochrane  feed-water  heater. 


ENGINEERING    CHEMISTRY  617 

carbonates.  These  substances,  therefore,  precipitate  and  adhere 
to  the  trays  over  which  the  water  flows  or  settle  in  the  sedimenta- 
tion chamber,  or  are  arrested  by  the  filter  in  the  lower  part  of 
the  latter. 


Fig.  115.— The  oil  separator  and  drain. 

The  hot  process  system  extends  the  treatment  to  include  the 
modification  of  sulphates,  carbonates,  nitrates  and  acids.  In  all 
cases  where  carbonates  are  present  in  any  considerable  quantity 
some  chemical  means  are  used  for  bringing  about  their  complete 
transformation  and  removal.  In  large  plants  this  reagent  is 
usually  milk  of  lime,  and  in  small  plants  it  may  be  either  milk 
of  lime  or  sodium  hydrate.  In  a  certain  number  of  cases,  sodium 
hydrate  is  the  only  chemical  required,  as  the  sodium  carbonate 
resulting  from  the  action  of  the  hydrate  with  the  lime  and  mag- 
nesium carbonate  is  about  sufiicient  to  take  care  of  sulphates, 
chlorides  and  nitrates  that  may  be  present.  The  reactions  take 
place  much  more  quickly  in  a  hot  solution  than  in  a  cold  one,  so 
that  less  storage  and  settling  capacity  are  required  in  a  hot  pro- 
cess system  than  in  a  cold  process  system.  The  same  fact  is 
illustrated  by  the  practice  with  some  cold  process  of  heating 
the  water  in  order  to  hasten  and  complete  the  reaction. 

Combining  the  action  of  the  water  with  the  chemical  treat- 
ment has  two  important  advantages  from  the  point  of  view  of 
softening  water  for  boiler  feeding: 

1st,  it  saves  the  cost  of  reagents  for  precipitating. 


6l8  ENGINEERING   CHEMISTRY 

2nd,  the  same  apparatus  performs  the  duties  of  both  softening 
system  and  open  feed-water  heater. 

The  open  heater  may  also  act  as  a  hot  well  for  condensed 
returns  from  heating  or  drying  systems,  or  for  condensate  from 
surface  condensers,  or  in  fact,  for  any  other  water  about  a  plant 
suitable  for  boiler  feeding.  This  is  an  advantage,  not  only  from 
the  point  of  view  that  it  simplifies  and  reduces  the  cost  of  the 
apparatus,  but  also  because  the  utilization  of  condensed  steam 
reduces  by  that  much  the  amount  of  raw  water  to  be  treated. 
Treating  with  one  chemical  instead  of  two,  where  practicable,  is 
also  a  great  advantage  from  the  point  of  view  of  practical  opera- 
tion, for  while  it  is  a  comparatively  complicated  matter,  requiring 
some  special  knowledge  and  skill,  to  analyze  water  for  its  several 
constituents  and  to  proportion  the  feed  of  two  reagents  in  accord- 
ance therewith,  it  is  a  comparatively  simple  matter  to  determine 
whether  or  not  the  feed  of  a  single  reagent  has  been  sufficient  to 
neutralize  the  substance  with  which  it  reacts. 

Fig.  ii6  illustrates  the  apparatus.  The  water  enters  through 
the  pipe  marked  ''Water  Supply"  and  empties  into  a  dis- 
tributing trough  in  the  upper  part  of  the  upright  section. 
From  this  trough  it  overflows  upon  alternately  inclined  trays, 
finally  dropping  into  the  settling  chamber  below.  During  this 
time  it  is  surrounded  on  all  sides  and  mingled  with  exhaust  steam 
which  has  entered  through  the  oil  separator  on  the  left.  Air  and 
gases  are  driven  out  of  the  water  and  any  surplus  of  steam 
escapes  through  the  vertical  outlet  pipe  at  the  top.  The  chemical 
reagent  is  intoduced  into  the  cold  water  supply  pipe  in  various 
ways.  The  latest  practice  provides  an  automatic  device  con- 
trolled by  the  rate  at  which  raw  water  enters  a  pump  drive  and 
the  chemicals  to  this  device  from  a  tank  where  the  materials  are 
kept  in  suspension  by  a  power  agitator.  A  dilute  solution  is  em- 
ployed, that  is,  not  near  the  saturation  point,  as  it  does  not  give 
trouble  from  clogging  the  valves,  which  concentrated  solutions 
sometimes  do.  The  size  of  the  settling  chamber  is  determined 
more  or  less  by  experience  with  waters  like  the  one  which  is  to 
be  treated,  more  time  being  required  for  the  settling  of  some  pre- 
cipitates than  for  others.     The  settling  tank  has  a  cylindrical 


ENGINEERING   CHEMISTRY 


619 


steel  plate  tank,  containing  an  inverted  cone.  As  the  treated 
water  falls  from  the  trays  it  is  mingled  with  the  reagent,  passes 
down  through  the  center  of  the  cone  to  a  filter  chamber  which  is 
placed  between  the  heater  chamber  and  the  sedimentation  and 
reaction  tank.  Above  the  filter  beds  is  the  pump  supply  chamber, 
and  in  this  chamber  is  a  copper  float,  controlling,  through  a  sys- 
tem of  levers  and  rods,  a  valve  in  the  cold  water  supply  pipe,  so 
that  when  the  pumps  draw  water  from  this  chamber  an  equiva- 
lent amount  of  water  is  admitted  to  the  distribution  trough  for 
treatment. 


Fig.  116.— Cochrane  metering  heater  with  outside  chamber  for  recorder  float. 

In  order  to  provide  for  a  supply  of  water  to  the  pumps  in 
case  the  filter  should  become  clogged  up,  a  supplementary  over- 
flow is  used  which  can  be  seen  attached  to  the  vertical  partition. 
The  action  of  this  is  as  follows : 

When  the  water  level  in  the  pump  supply  chamber  is  drawn 
down  by  the  pumps,  the  float  opens  the  cold  water  regulating 
valve  and  the  water  consequently  flows  into  the  settling  chamber 
at  the  left.  If  the  filter  does  not  allow  the  water  to  pass  though 
at  a  corresponding  rate,  it  will  rise  in  this  chamber  until  it  reaches 
the  supplementary  by-pass  and  overflows  directly  into  the  pump 
supply  chamber,  thus  insuring  for  the  pumps  hot,  treated  and 
settled  water,  no  matter  to  what  extent  the  filter  may  be  neglected. 


620 


ENGINEERIxNG    CHEMISTRY 


Another  feature  of  the  apparatus  is  the  overflow  trap  attached 
at  the  left  end.  Where  the  apparatus  is  working  under  back 
pressure,  as  in  connection  with  an  exhaust  steam  heating  or  dry- 
ing system,  there  is  a  trap  as  here  shown.  If,  however,  the  ex- 
haust outlet  from  the  apparatus  is  open  to  atmosphere,  a  water 
seal  will  answer  the  purpose,  which  is  to  drain  the  oily  emulsion 
separated  from  the  steam  in  the  oil  separator,  to  drain  the  waste 
and  to  dispose  of  the  overflow  from  the  heater  itself,  while  pre- 
venting free  escape  of  steam.  In  fact,  it  is  customary  to  over- 
flow the  heater  for  a  short  period  each  day  by  holding  open  the 
cold  water  valve  until  the  water  level  in  the  settling  chamber 
rises  to  the  edge  of  the  overflow  weir,  this  disposing  of  any  scum 
or  other  impurities  floating  on  the  surface. 

Summary  ok  Purifying  Results  Obtained  in  the  Hot 
Process  System. 


Substance  in  Feed  Water 


Calcium  bicarbonate,  CaiHCOgJa- 
Calcium  sulphate,  CaSOi 


Calcium  chloride,  CaClj^ 


Calcium  nitrate,  Ca( N03)2 

Magnesium  bicarbonate,  Mg(HC03)2- 


Magnesium  sulphate,  Mg(S04' 


Magnesium  chloride,  MgCla  • 
Iron  bicarbonate,  Fe(HC03)2 


Silica,  SiOa 

Clay,   HgAlaSijOg •  •• 

Mineral  acids 

Carbonic  acid 

Hydrogen  sulphide. 

Air 

Organic  and  Oily  acids-  • 


Trouble  in  Boiler 


Soft  Scale 
Hard  Scale 

Indirectly  may 
cause  corrosion 

Corrosion 
Soft  scale  and 

foaming 

Indirectly  may 

cause  scale 

Corrosion' 

Sludge 

Sludge 

Sludge 
Corrosion 
Corrosion 
Corrosion 
Corrosion 
Corrosion 


Remedied  by 


Caustic  soda  or  lime 

Heat  and  soda 

ash 

Soda  ash 

Soda  ash 
Caustic  soda  or  lime 

Heat  and  soda 

ash 

Soda  ash 

Contact  with 

air  and  heat 

Filter 

Filter 

Soda  Ash 

Heat 

Heat 

Heat 

Soda  ash 


1937. 


References—"  How  Should  Feed  Water  be  Heated?  "  by  A.  J.  Albright,  Power,  July 

"The  Paterson  Oil  Eliminator  and  Water  Softener,"  Engineering,  Dec. 

21. 1906. 


ENGINEERING    CHEMISTRY 


621 


Trouble  Due  to  Water:    Prevention  and  Cure^ 


Trouble 


INCRUSTATION 


Cause.  Cure 

f  Sediment,  mud,  clay,  etc.      Filtration 
I   Readily  soluble  salts  Blowing-off 

{  Heating  feed  and  precip-^ 
itate 
Caustic  soda 


\   Bicarbonate  of  magnesia,   j 

j       Lime,  iron  Lime 

I  ^  Magnesia 


Organic  matter 
Sulphate  of  lime 


See  below 

\  Sodium.  Carbonate 
\  Barium  chloride 


Corrosion 


f  Organic  matter^ 
Grease 


Chloride  or  sulphate 
\       magnesium 
.   Sugars 

Acid 


Precip.  with  alum " 
Precip.  with  ferric 
chloride 

Slaked  lime 
Sodium  Carbonate 


of 


and 
filter 

and 
filter 


Sodium,  Carbonate 


Sodium  Cafbonate 


Dissolved    carbonic 
and  oxygen^ 

I  Electrolytic  action^ 


acid 


Slaked  lime 
Caustic  soda 
Heating 
Zinc  plates 


Priming 


f  Sewage 

'   Alkalies 

I  Carbonate     of    soda 
y      large  quantities 


Precipitate  with  alum  or 
ferric  chloride  and  filter 


Heating   Feed 
cipitate 


and    Pre- 


Barium  chloride 


1  Compiled  by  Prof  S   M   Noiton 

3  Organic  acids  are  neutralized  by  soda  ash.— Ed. 

^  Note.— Recent  investigations  have  shown  that  electrolytic  corrosion  in  aqueous  solu- 
tions is  generally  conditional  upon  the  presence  of  oxygen  The  latter  is  expelled  from 
the  water  by  heating  in  the  Cochrane  heater.— Ed. 


612 


Engine:ering  chemistry 


H.  De  La  Coux/  states :  "Sodium  silicate  which  has  been 
proposed  as  a  scale  preventative  is  transformed  in  the  presence 
of  the  carbonate  of  calcium  in  the  water  into  silicate  of  calcium 
and  falls  down  in  a  white  gelatinous  precipitate : — 

NaoSi03  +  Ca(HC03),  =  CaSiO^  +  CO,  +  H^O  +  Na^COa- 

With  ordinary  waters  scale  can  be  prevented  by  the  addition 
of  600  grams  of  silicate  of  sodium  solution  of  35°  B.  per  horse- 
power per  month." 


Table  Showing  the   Yearly   Saving   Effected   by  the  Use   of  the 

Feed-Water  Heater  for  Various  Horse-Powers  and  at 

Different  Prices  of  Coal 


Coal  consump- 

Horse 

power 

of 

tion  at  4 

pounds  per 

H.  P.  per  hour 

Saving 

ofi3^ 

per 

cent. 

Price  of  coal  per  ton  of  2,240  pounds 

engine 

Daily 

Yearly 

$1.50 

$2.00 

$2.50 

$5.00 

$3-50 

$4.00 

$4.50 

15.00 

$5-50 

$6.00 

Lbs. 

Tons 

Tons 

50 

2000 

268 

36.18 

1  54 

$   72 

$   90 

|io8 

$126 

M45 

I163 

|i8i 

$199 

$217 

60 

2400 

321 

43-33 

65 

87 

108 

128 

152 

173 

194 

217 

238 

260 

70 

2800 

375 

50.62 

76  lOI 

126 

152 

177 

202 

227 

253 

278 

304 

80 

3200 

429 

57.91 

.  871  116 

145 

177 

203 

232 

261 

289 

318 

347 

100 

4000 

536 

72.36 

108  145 

187 

217 

253 

289 

325 

362 

398 

434 

120 

4800 

643 

86.80 

130!  174 

217 

260 

304 

347 

390 

434 

477 

521 

160 

6400 

857 

115.69 

173!  231 

289 

347 

404 

463 

520 

578 

635 

694 

200 

8000 

1072 

144.72 

217 

289 

362 

434 

506 

579 

651 

724 

796  868 

250 

1 0000 

1340 

185.90 

279 

372 

465 

558 

651 

744 

837 

929 

1022  1115 

300 

12000 

1608 

226.08 

339 

452 

565 

678 

791 

904 

1017 

1 130 

1243 

1356 

350 

14000 

1876 

253-26 

380!  506 

633 

760 

886 

1013 

1139 

1266 

1392 

1.519 

400 

16000 

2144 

289.44 

4341  579 

723 

868 

1013 

1158 

1302 

1447 

1591 

1730 

500 

20000 

2680 

361.80 

543 

724 

904 

1085 

1267 

1447 

1627 

1809 

1990 

2170 

600 

24000 

3216 

433-30 

650 

867 

1083 

1300 

1517 

1733 

1950 

2170 

2387 

2600 

700 

28000 

3752 

506.20 

759 

1012 

1265 

1518 

1771 

2025 

2278 

2531 

2784 

3037 

800 

32000 

4288 

579-10 

868 

1158 

1448 

1737 

2026 

2316 

2605 

2895 

3184 

3474 

900 

36000 

4824 

651.24 

977 

1302 

1628 

1954 

2279 

2605 

2930 

3256 

3581 

3907 

1000 

40000 

5360 

723.60 

1085 

1447 

1809 

2170 

2532 

28943255 

3618 

3990; 4341 

'Industrial  Uses  of  Water,"  p  49 


ENGINEERING   CHEMISTRY 


623 


Percentage  of  Fuei,  Saved  by  Heating  Feed  Water 
(Steam  pressure  60  pounds) 


I 


«  s 

^  s 

(U  V.  1- 

ill 

'^  s  * 

ill 

Temperature  of  water  entering  boiler 

%%t 

-•Si; 

120°  F 

140°  F 

160°  F 

iSqOF 

200°  F 

202°  F 

204°  F 

206°  F 

208°  F 

210°  F 

212°  F 

214OF 

216°  F 

32° 

1175 

7.49 

9.19 

10.89 

12.59 

14.30 

14.47 

14.64 

14.81 

14.98 

15.15 

15.32 

15.49 

15.66 

40" 

1 1 67 

6.86 

«-57 

10.28 

12.00 

13.71 

I3.88I14.O5 

14.22 

14.40 

14.57 

14.74 

14.91 

15.08 

50^ 

1157 

6.05 

7.7« 

9-51 

11.24 

12.97 

I3.I4I3.32 

13.49 

13.66 

13.83 

14.00 

14.18 

14.35 

60" 

1147 

5.23 

6.97 

8.72 

10.46 

12.21 

12.38 

12.55 

12.73 

12.90 

13.08 

13.25 

13.43 

13.60 

70" 

1 137 

4.41 

6.16 

7.91 

9.67 

11.43 

II. 61 

11.78 

11.96 

12.14 

12.31 

12.49 

12.66 

12.84 

80" 

1127 

3.44 

5-32 

7.10 

8.87 

10.65 

10.82 

11.00 

II. 18 

11.36 

11.53 

II. 71 

11.89 

12.07 

90° 

1117 

2.68 

4-47 

6.26 

8.06 

9«5 

10.03 

10.21 

10.38 

10.56 

10.74 

10.92 

II. 10 

11.28 

iOO" 

1 107 

1.80 

3.61 

5.42 

7.23 

9-03 

9.21 

9-39 

9-57 

9-75 

9.93 

10.  II 

10.29 

10.47 

110° 

1097 

0.91 

2.73 

4.55 

6.38 

8.20 

«.3« 

8.58 

8.74 

8.93 

9.II 

9.29 

9-47 

9.66 

120" 

1087 

1.84 

3.67 

5-51 

7.35 

7.54 

7.77 

7.90 

8.09 

8.27 

8.45 

8.64 

8.82 

FUEL  ECONOMIZERS. 

A  fuel  economizer  generally  consists  of  a  nest  of  vertical  iron 
tubes  arranged  in  the  flue  leading  to  the  chimney  and  utilizing 
the  otherwise  wasted  heat  in  the  gases  of  combustion. 

It  is  able  to  recover  low  temperature  heat  that  would  escape 
or  has  escaped,  a  boiler,  because  of  the  fact  that  the  average 
temperature  of  the  water  within  the  tubes  of  the  economizer 
is  much  lower  than  the  temperature  of  the  water  in  a  boiler.  This 
fundamental  principle  of  heating  the  feed  water  in  a  separate 
vessel  apart  from  the  boiler  and  thereby  saving  the  heat  in  the 
waste  gases  passing  to  the  chimney  is  the  distinctive  invention  of 
Mr.  Edward  Green,  who  made  his  first  experiments  upon  an 
apparatus  for  this  purpose  m  1845.^ 

The  maximum  possible  saving  by  an  economizer  is  based  upon 
the  assumption  that  the  construction  of  the  economizer  unfits  it 
for  the  generation  of  steam,  but  that  it  may  be  allowed  to  do  all 
the  work  of  heating  the  water  up  to  the  boiler  evaporating  tem- 
perature. In  a  certain  plant  tested,  the  boiler  pressure  was  95 
lbs.,  the  corresponding  temperature  of  evaporation  being  334° 
F.     The  temperature  of  the  feed  water  entering  the  economizer 

1  The  Book  of  the  Economizer,  p.  5 


Kngine;e:ring  che:mistry  625 

was  162.5°  F.,  so  that  it  was  theoretically  possible  for  the  econ- 
omizer to  contribute  334.  minus  162.5  =^  i7i-5  British  thermal 
units.  The  number  of  thermal  units  required  for  the  actual 
evaporation  of  water  at  95  lbs.,  is  887.9.  The  total  work  done 
on  the  water  is  therefore  887.9  plus  17 1.5  —  1049.4  heat  units, 
of  which  171. 5  constitutes  16.3  per  cent.,  or  the  maximum  pro- 
portion of  the  work  that  could  be  done  by  the  economizer  re- 
ceiving water  at  162.5°  F.,  which  was  the  actual  temperature, 
the  water  in  this  case  coming  from  an  open  heater  where  it  had 
been  warmed  by  the  exhaust  of  the  pumps  and  certain  other 
auxiliary  apparatus. 

WITH   HIGH   pressure:  AND  SUPERHEAT. 

With  a  steam  pressure  of  200  lbs.  and  a  feed-water  temper- 
ature of  60°  F.  the  case  figures  out  as  follows :  The  temperature 
of  evaporation  for  200  lbs.  gauge  pressure  is  387.5°  F.  The 
latent  heat  of  evaporation  is  839  British  thermal  units.  The 
heat  that  can  be  contributed  by  the  economizer  is  333.2  British 
thermal  units.  The  economizer,  therefore,  can  contribute  28.4 
per  cent,  of  the  total  amount  of  heat  required  to  convert  the 
water  from  60°  into  steam  at  200  lbs.  or,  looking  at  it  another 
way,  it  can  contribute  39.7  per  cent,  as  much  heat  as  does  the 
boiler.  This  is  the  theoretical  limit,  since  the  economizer  is  not 
expected  to  make  steam,  in  fact,  it  is  provided  with  a  safety  valve 
so  that  in  case  it  does  make  steam  the  latter  can  escape. 

It  should  be  noted,  however,  that  the  higher  the  steam  pres- 
sure, the  greater  the  work  of  the  economizer  may  be,  and,  on 
the  other  hand,  the  lower  the  efficiency  of  the  boiler  will  be,  if 
it  be  not  supplemented  by  an  economizer.  The  higher  the  steam 
pressure,  the  less  is  the  average  difference  in  temperature  between 
the  gases  of  combustion  and  the  contents  of  the  boiler,  therefore 
the  slower  the  transmission  of  heat. 

The  temperature  of  a  boiler  carrying  steam  at  80  lbs.  is  323.6° 
F.,  while  that  of  one  carrying  200  lbs.  is  387.5°.  The  temper- 
ature of  the  boiler  determines  the  lower  limit  to  which  the  gases 
may  be  cooled  before  they  pass  to  the  chimney,  since  no  matter 
how  much  the  boiler  surface  is  extended,  the  gases  cannot-  be 
40 


626  ENGINEERING    CHEMISTRY 

cooled  below  its  temperature.  The  higher  the  steam  pressure 
the  higher  is  the  limit  and  the  greater  must  be  the  amount  of 
heat  lost  to  the  chimney.  By  the  use  of  the  economizer  the 
temperature  of  the  flue  gases  may  be  reduced  to  almost  any  ex- 
tent, having  the  temperature  of  the  cold  feed  water  as  the  lower 
limit.  As  usually  proportioned,  the  temperature  of  the  gases 
leaving  the  economizer  is  from  240°  to  235°  F. 

High  steam  pressure  and  superheat  unquestionably  save  steam. 
It  has  been  shown  that  a  single  cylinder  non-condensing  en- 
gine can  be  run  on  about  16  lbs.  of  superheated  steam  per 
indicated  horse-power  and  a  triple  condensing  engine  on  as  low 
as  8.75  lbs.  Steam  turbines  have  been  operated  with  less  than 
10  lbs.  per  brake  horse-power,  but  this  good  steam  economy  does 
not  mean  good  fuel  economy  if  the  flue  gases  are  allowed  to 
escape  at  a  high  temperature.  M.  Dejace  reports  that  with  a 
superheat  of  473°  F.  a  saving  of  16.4  per  cent,  of  steam  was 
realized,  but  the  saving  of  coal  was  only  6.2  per  cent.  Tests  by 
G.  H.  Barrus  on  Curtis  turbines,  with  150°  F.  superheat  at  the 
throttle,  show  10  per  cent,  of  steam  saved  and  less  than  i  per 
cent,  of  coal  saved.  The  saving  of  coal  does  not  pay  for  the  in- 
convenience of  superheat.  While  comparatively  little  heat  is 
required  merely  to  superheat  steam,  perhaps  not  more  than  one- 
third  as  much  as  to  pre-heat  the  boiler  feed,  much  heat  is  usually 
wasted  in  the  process  of  superheating,  since  the  gases  from  which 
the  steam  receives  its  heat  must  be  hotter  than  the  steam  itself. 
Starting  with  the  temperature  for  200-lb.  pressure  steam,  that 
is,  387.5°  F.,  suppose  we  add  5CX)°  superheat,  this  gives  a  tem- 
perature of  887°  F.  and  the  gases  leaving  he  superheater  must 
still  be  hotter.  If  the  superheater  is  placed  beyond  the  boiler  or 
is  heated  by  a  separate  furnace  there  will  necessarily  be  a  great 
loss  of  heat.  If  the  superheater  is  located  between  the  "passes" 
of  the  boiler,  an  arrangement  having  some  disadvantages,  the 
final  temperature  of  the  gases  may  be  lessened  to  a  certain  extent 
by  the  addition  to  the  heating  surface  represented  by  the  super- 
heater, but  if  the  steam  pressure  is  high  the  gases  will  still  be  very 
hot.  The  economizer,  however,  will  recover  all  the  waste  heat 
resulting   from   high   pressure   or   superheat,   besides   recovering 


ENGINEJERING    CHE;mISTRY  627 

enough  more,  as  in  ordinary  plants,  to  pay  for  itself  in  from  two 
to  three  years.  The  economizer  makes  the  fuel  saving  correspond 
to  the  steam  saving  of  the  engine  and  a  superheated  steam  plant 
is  incomplete  without  it.  Where  superheat  is  to  be  used  a  good 
arrangement  is  as  follows :  the  boiler  should  be  operated  at  a  high 
rate  so  that  the  gases  will  leave  at  a  high  temperature,  then  fol- 
lowing the  boiler  there  should  be  the  superheater  and  after  the 
gases  leave  the  superheater  they  should  pass  through  an  econo- 


GAS  ANALYSIS. 


Analysis  of  Chimney  Gases  for  Oxygen,  Carbon  Dioxide, 
Carbon  Monoxide  and  Nitrogen. 

Revised  by  Thomas  B.  Stillman,  Jr.,  M.S. 

The  determinations  usually  made  are  the  percentages,  by 
volume,  of  oxygen,  carbon  dioxide,  carbon  monoxide,  and  nitro- 
gen. 

The  apparatus  used  (a  modified  form  of  the  Elliott)  is  shown 
in  Fig.  118,  and  consists  of  two  glass  tubes,  ib  and  ah,  the  tube  ib 
having  a  capacity  of  about  125  cc.  and  is  accurately  graduated 
from  o  cc.  to  100  cc.  in  o.i  cc.  At  d  and  e  are  three-way  glass 
stop-cocks,  connected  by  means  of  rubber  tubing  in  the  water- 
supply  bottles,  /  and  g.  The  manipulation  of  the  apparatus  is  as 
follows : 

Remove  the  funnel  cap  c,  and  connect  in  its  place  a  glass  tube 
of  small  diameter,  but  of  sufficient  length  to  each  well  into  the 
flue  from  which  the  gases  are  to  be  taken.  Open  the  stop-cocks 
a  and  b  and  slowly  raise  g  and  /  until  both  tubes  are  full  of  water 
including  the  glass  tube  in  the  flue.  It  is  necessary  in  this  oper- 
ation to  be  certain  that  no  air  is  in  the  tubes  and  that  the  dis- 
placement by  water  is  complete.  Now  gradually  lower  the  bottle 
/  whereby  the  gas  is  drawn  into  the  tube  ah.  As  soon  as  suf- 
ficient gas  has  been  obtained  for  the  analysis,  the  lower  por- 
tion of  the  tube  containing  water  2  or  3  inches  above  the  point 

J  The  book  of  the  Economizer,  pp.  35-37. 


628 


Engine;ering  chemistry 


h,  the  stop-cock  a  is  closed,  the  small  glass  tube  connecting  a 
with  the  flue  removed,  and  the  funnel  cap  c  replaced.     After 


allowing  the  gas  to  stand  in  the  tube  ah  fifteen  minutes  to  acquire 
the  temperature  of  the  room,  and  thus  insure  correct  measure- 
ments, the  bottle  g  is  slowly  lowered  until  the  surface  of  the 


I 


ENGINEERING    CHEMISTRY  629 

water  therein  is  on  an  exact  level  with  o  on  the  tube  ib,  the  stop- 
cock b  opened  and  the  bottle  /  gradually  raised  until  sufficient 
gas  from  ah  has  been  transferred  to  bi,  indicated  by  the  volume 
taken  reading  from  the  mark  o  on  the  graduated  tube  ib  to  the 
mark  100  cc.  immediately  in  contact  with  the  stop-cock,  b. 

Having  thus  obtained  100  cc.  of  the  gas,  the  stop-cock  b  is 
closed  and  /  is  raised  until  all  the  remaining  gas  in  ah  and  ab  is 
displaced  by  the  water.  The  first  constituent  of  the  gas  to  be 
determined  is  carbon  dioxide  (CO,).  The  gas  is  now  trans- 
ferred to  the  tube  ah  by  raising  g  and  opening  b,  keeping  a  closed 
and  /  lowered.    When  the  water  reaches  b  the  latter  is  closed. 

Fifty  cc.  of  a  solution  of  caustic  potash  are  placed  in  the  funnel 
cap  c.  (The  solution  is  made  by  dissolving  280  grams  of  potas- 
sium hydrate  in  1,000  cc.  of  distilled  water.) 

Open  the  stop-cock  a  only  partially,  so  that  the  solution  of 
caustic  potash  in  c  may  slowly  drop  down  through  the  gas  in  the 
tube  ah  and  absorb  the  carbon  dioxide  in  so  doing. 

When  all  the  caustic  potash  solution  in  c  (with  the  exception 
of  2  or  3  cc.)  has  passed  through  a,  the  latter  is  closed,  thus  pre- 
venting entrance  of  any  air ;  b  is  opened,  /  is  slowly  raised  and  g 
lowered.  Continue  the  raising  of  /  until  the  water  in  the  tube 
ha  reaches  the  stop-cock  b  and  immediately  close  the  latter. 
Allow  the  gas  to  stand  in  the  tube  ib  five  minutes  before  taking 
the  reading  of  the  volume  on  the  tube,  bearing  in  mind  that  the 
level  of  the  water  in  g  must  be  on  a  level  with  the  water  in  ib  to 
obtain  equal  pressure.  The  difference  between  o  and  the  point 
indicated  by  the  water  in  the  tube  ib  will  give  the  amount  of  car- 
bon dioxide  absorbed  from  the  gas  by  the  caustic  potash.    Thus : 

cc. 

Original  volume  indicated  at 0.0 

After  removal  of  carbon  dioxide '. . .   12.2 

or  12.2  per  cent,  carbon  dioxide  by  volume. 

To  obtain  the  oxygen  the  gas  is  forced  from  ib  into  ah,  as 
before,  and  in  c  is  placed  50  cc.  of  an  alkaline  solution  of  pyro- 
gallic  acid. 

This  latter  solution  is  formed  by  dissolving  10  grams  of  pyro- 


630  ENGINEERING   CHEMISTRY 

gallic  acid  in  25  cc.  of  distilled  water,  placing  it  in  c  and  adding 
35  cc.  of  the  caustic  potash  solution.  This  is  allowed  to  pass 
slowly  through  a  and  gradually  absorbs  the  oxygen  in  the  gas. 
a  is  closed  before  all  the  liquid  passes  out  of  c.  Repeat  with  the 
same  quantity  of  alkaline  pyrogallic  solution.  Transfer  the  gas 
in  the  usual  manner  to  ib,  and  after  allowing  to  stand  five  minutes, 
take  the  measurement  thvis  : 

cc. 
Previous  reading 12.2 

After  absorbing  oxygen   19. i 

Oxygen   6.9 

or  6.9  per  cent,  by  volume. 

Before  transferring  the  gas  to  ah  for  the  determination  of  the 
carbon  monoxide,  all  the  water  in  /  and  ah  must  be  replaced  by 
distilled  water  ;^  to  do  this,  open  the  three-way  cock  e,  open  a 
and  all  the  water  can  be  caught  in  a  large  beaker  at  e.  Wash 
out  /  and  ah  three  times  with  the  water,  then  close  e  in  the 
proper  manner  so  that  the  water  placed  in  /  will  rise  in  the  tube 
ha  to  a,  then  close  a,  lower  /,  raise  g,  open  b,  placing  the  gas  in 
ah  for  treatment  with  a  solution  of  cuprous  chloride  to  determine 
the  carbon  monoxide. 

The  cuprous  chloride  solution  is  made  by  dissolving  30  grams 
of  cuprous  oxide  in  200  cc.  hydrochloric  acid  specific  gravity 
(1.19),  and  using  50  cc.  as  soon  as  the  solution  has  reached  the 
temperature  of  the  room. 

Experience  has  shown  that  a  freshly  made  solution  acts  much 
better  in  an  absorbent  of  carbon  monoxide  than  one  that  has  stood 
several  days.  Fifty  cubic  centimeters  of  this  solution  are  placed 
in  c  and  allowed  to  drop  slowly  through  a  and  absorb  the  carbon 
monoxide  as  it  passes  through  the  gas.  This  absorption  should  be 
repeated  at  least  three  times.  The  heat  generated  during  this  ab- 
sorption often  causes  such  an  increase  in  the  volume  of  the  gas 
that  when  the  latter  is  transferred  to  the  tube  ib  for  measurement, 

'  The  water  used  in  the  apparatus  at  the  commencement  of  the  gas  analysis  should 
be  saturated  with  the  gas.  After  determination  of  carbon  dioxide,  distilled  water  can  be 
used.     Con.sult  foot  note  on  page  632. 


ENCxINI^ERING   CHEMISTRY  63I 

the  reading  may  prove  minus.     To  insure  accuracy  proceed  as 
follows : 

The  gas,  after  fifteen  minutes,  is  transferred  in  the  usual  way 
to  bi,  and  the  water  in  /  and  ah  is  replaced  with  distilled  water. 
The  gas  is  now  returned  to  ah  and  a  solution  of  potassium  hy- 
droxide is  placed  in  c  and  allowed  to  pass  through  the  gas  in  ah, 
absorbing  all  traces  of  hydrochloric  acid  gas.  Repeat  with  this 
once.  Return  the  gas  to  bi,  allow  to  stand  fifteen  minutes,  then 
take  the  reading : 

cc. 

Previous  reading 19.I 

After  using  CU2CI2  solution 19.5 

CO 0.4 

The  nitrogen  is  determined  by  subtracting  the  total  amounts  of 
carbon  dioxide,  oxygen,  and  carbon  monoxide  from  loo. 
Thus  the  analysis  will  read : 

Per  cent, 
by  volume 

Carbon  dioxide    12.2 

Oxygen 6.9 

Carbon  monoxide   4 

Nitrogen    80.5 

Total   loo.o 

In  this  analysis  no  corrections  are  required  for  the  tension  of 
the  aqueous  vapor,  since  the  original  gas  is  saturated  with  mois- 
ture, and  during  the  analysis  all  measurements  are  made  over 
water. 

^Apparatus  for  Flue  Gas  Analysis. — The  Orsat  apparatus  il- 
lustrated in  Fig.  119,  is  the  one  most  frequently  used  for  analyzing 
flue  gases.  The  burette  A  is  graduated  in  cubic  centimeters  up  to 
100,  and  is  surrounded  by  a  water  jacket  to  prevent  any  change  in 
temperature  from  affecting  the  density  of  the  gas  being  analyzed. 

For  accurate  work  it  is  advisable  to  use  four  pipettes,  B,  C, 
D,  B,  the  first  containing  a  solution  of  caustic  potash  for  the 
absorption  of  carbon  dioxide,  the  second  an  alkaline  solution  of 

1  From  the  35th  Edition  of  Steam  published  by  the  Babcock  &  Wilcox  Company,  New- 
York. 


632 


ENGINEERING    CHEMISTRY 


pyrogallol  for  the  absorption  of  oxygen,  and  the  remaining  two 
an  acid  solution  of  cuprous  chloride  for  absorbing  the  carbon 
monoxide.^  Each  pipette  contains  a  number  of  glass  tubes,  to 
which  some  of  the  solution  clings,  thus  facilitating  the  absorp- 
tion of  the  gas.  In  the  pipettes  D  and  B,  copper  wire  is  placed 
in  these  tubes  to  re-energize  the  solution  as  it  becomes  weakened. 


Fig.  119  — Orsnt  apparatus. 


The  rear  half  of  each  pipette  is  fitted  with  a  rubber  bag,  one  of 
which  is  shown  at  K,  to  protect  the  solution  from  the  action  of 

1  The  proportion.s  used  by  the  Babcock  &  Wilcox  Co.    in  preparing  sohitious  for  use 
the  Orsat  apparatus  are  as  follows  : 
(i)  For  the  absorption  of  COo 

I  gram  of  KOH  (.Sticks)  dissolved  in  2  grams  of  water. 

(2)  For  the  absorption  of  O. 

I  gram  of  Pyrogallic  acid  dissolved  in  3  grams  of  water. 
2,  grams  of  KOH  dissolved  in  2  grams  of  water. 

Mix  these  two  solutions  in  the  Orsat  pipette  in  the  proportion  of  15  cc.  of 
the  acid  to  35  cc.  of  KOH. 

(3)  Mix  5  grams  of  water  and  3  grams  of  Cuprous  chloride.    To  this  add   15  cc.  or  13 
grams  of  con.  HCIy  (sp.  gr.  1.2)  and  place  in  bottle  with  copper  gauze. 

Use  when  liquid  is  clear. 


DNGINEKRING    CHEMISTRY  633 

the  air.     The  solution  in  each  pipette  should  be  drawn  up  to  the 
mark  on  the  capillary  tube. 

The  gas  is  drawn  into  the  burette  through  the  U-tube  H,  which 
is  filled  w4th  spun  glass,  or  similar  material,  to  clean  the  gas.  To 
discharge  any  air  or  gas  in  the  apparatus,  the  cock  G  is  opened 
to  the  air  and  the  bottle  F  is  raised  until  the  water  in  the  burette 
reaches  the  lOO  cc.  mark.  The  cock  G  is  then  turned  so  as  to 
close  the  air  opening  and  allow  gas  to  be  drawn  through  H,  the 
bottle  F  being  lowered  for  this  purpose.  The  gas  is  drawn  into 
the  burette  to  a  point  below  the  zero  mark,  the  cock  G  then  being 
opened  to  the  air  and  the  excess  gas  expelled  until  the  level  of 
the  water  F  and  in  A  are  at  the  zero  mark.  This  operation  is 
necessary  in  order  to  obtain  the  zero  reading  at  atmospheric 
pressure. 

The  apparatus  should  be  carefully  tested  for  leakage  as  well  as 
all  connections  leading  thereto.  Simple  tests  can  be  made;  for 
example:  If  after  the  cock  G  is  closed,  the  bottle  F  is  placed  on 
top  of  the  frame  for  a  short  time  and  again  brought  to  the  zero 
mark,  the  level  of  the  water  in  A  is  above  the  zero  mark,  a  leak 
is  indicated. 

Before  taking  a  final  sample  for  analysis,  the  burette  A  should 
be  filled  with  gas  and  emptied  once  or  twice,  to  make  sure  that  all 
the  apparatus  is  filled  with  the  new  gas.  The  cock  G  is  then  closed 
and  the  cock  /  in  the  pipette  B  is  opened  and  the  gas  driven  over 
into  B  by  raising  the  bottle  F,  The  gas  is  drawn  back  into  A  by 
lowering  F  and  when  the  solution  in  B  has  reached  the  mark  in 
the  capillary  tube,  the  cock  /  is  closed  and  a  reading  is  taken  on 
the  burette,  the  level  of  the  water  in  the  bottle  F  being  brought 
to  the  same  level  as  the  water  in  A.  The  operation  is  repeated 
until  a  constant  reading  is  obtained,  the  number  of  cubic  centi- 
meters being  the  percentage  of  CO2  in  the  flue  gases. 

The  gas  is  then  driven  over  into  the  pipette  C  and  a  similar 
operation  is  carried  out.  The  difference  between  the  resulting 
reading  and  the  first  reading  gives  the  percentage  of  oxygen  in 
the  flue  gases. 

The  next  operation  is  to  drive  the  gas  into  the  pipette  D,  the 


634  ENGINEERING   CHEMISTRY 

gas  being  given  a  final  wash  in  B,  and  then  passed  into  the  pipette 
B  to  neutraHze  any  hydrochloric  acid  fumes  which  may  have  been 
given  off  by  the  cuprous  chloride  solution,  which,  especially  if 
it  be  old,  may  give  off  such  fumes,  thus  increasing  the  volume  of 
the  gases  and  making;  the  reading  on  the  burette  less  than  the  true 
amotmt. 

The  process  must  be  carried  out  in  the  order  named,  as  the 
pyrogallol  solution  will  also  absorb  carbon  dioxide,  while  the 
cuprous  chloride  solution  will  also  absorb  oxygen. 

As  the  pressure  of  the  gases  in  the  flues  is  less  than  the  atmos- 
pheric pressure,  they  will  not  of  themselves  flow  through  the  pipe 
connecting  the  flue  to  the  apparatus.  The  gas  may  be  drawn  into 
the  pipe  in  the  way  already  described  for  filling  the  apparatus, 
but  this  is  a  tedious  method.  For  rapid  work  a  riibber  bulb 
aspirator  connected  to  the  air  outlet  of  the  cock  G  will  enable 
a  new  supply  of  gas  to  be  drawn  into  the  pipe,  the  apparatus  then 
being  filled  as  already  described.  Another  form  of  aspirator 
draws  the  gas  from  the  flue  in  a  constant  stream,  thus  insuring 
a  fresh  supply  for  each  sample. 

Several  improvements  in  construction  of  the  absorption  tubes 
of  the  Orsat-Muencke  gas  analysis  apparatus  have  been  made. 
Hankee's^  absorption  pipette  are  shown  in  Figs.  120  and  121. 

In  Fig.  120  is  shown  a  capillary  glass  tube  fused  into  the 
pipette  for  better  absorption,  which  reaches  nearly  to  the  base  and 
through  which  the  gas  passes.  A  small  glass  vessel  is  placed  un- 
der the  end  of  the  capillary  tube.  The  gas  comes  out  in  bubbles, 
disperses,  rises  through  the  absorbent  liquid  and  is  again  carried 
off  through  a  second  tube,  through  a  Geissler  stop-cock. 

R.  Nowicki-  has  added  to  the  Hankus  pipette  a  winding  glass 
tube  shown  in  Fig.  121.  The  gas  leaves  at  the  lower  end  though 
a  fine  opening,  rises  in  the  winding  tube,  always  presenting  new 
surfaces  for  absorption. 

Fig.  122  shows  the  complete  form  of  the  Hahn  apparatus  for 
gas  analysis. 

1  Stahl  and  Ei'sen,  23,  1,  261,  1903. 

2  Osteer.  Zeitschrift.  f,  Betg.  u.  Hultemv.,  1905. 


ENGINEERING    CHEMISTRY 


635 


In  using  this  apparatus  the  burette  M,  the  leveHng  vessel  JV, 
(contains  water),  and  the  glass  tube  surrounding  the  combustion 
tube  5,  is  also  filled  with  water.  The  absorption  pipettes  contain 
solution  as  follows  and  are  filled  about  one-half :  No.  i  contains 
a  solution  of  potassium  hydrate  in  water  (specific  gravity  1.26)  ; 
No.  2  contains  fuming  sulphuric  acid  (HoSoO^)  ;  No.  3  contains 
a  solution  of  alkaline  pyrogallate,  formed  by  dissolving  10  parts 
of  pyrogallic  acid  in  40  parts  of  hot  water  and  adding  70  parts  of 


!tA 


Fig.  120. 


Fig.  121. 


potassium  hydroxide  solution  (specific  gravity  1.26)  ;  No.  4  con- 
tains an  alkaline  solution  of  ammonia-cuprous  chloride. 

The  gas  tubing  introducing  the  gas  is  connected  at  G.  After 
raising  the  leveling  bottle  W  all  the  air  of  the  apparatus  is  dis- 
placed and  103  cc.  to  105  cc.  of  the  gas  is  measured  in  the  burette 
M,  and  the  excess  passed  out  so  that  100  cc.  remain  for  analysis. 
CO2  is  absorbed  in  pipette  No.  i.  Illuminants,  if  present,  are 
absorbed  in  pipette  No.  2,  then  passed  through  No.  i  again  before 


636 


KNGINKERING    CHEMISTRY 


measurement.  The  gas  is  then  passed  3  or  4  times  through  No. 
3,  before  measuring  for  determination  of  the  oxygen,  and  the 
same  in  using  pipette  No.  4  for  the  absorption  of  the  CO. 

For  the  hydrogen  determination  a  portion,  or  if  necessary,  all 
of  the  residual  gas  is  passed  over  the  heated  palladium  sponge  in 


Fig. 


c.  Two-thirds  of  the  reading  of  the  contraction  in  volume  of  the 
gas  represents  the  amount  of  hydrogen.  To  determine  the  me- 
thane, the  residual  gas  is  passed  in  combustion  tube  5,  the  plati- 
num wires  therein  heated  to  a  red  heat,  the  contained  gas  in  the 
meantime  being  brought  a  number  of  times  in  contact  with  the  hot 


ENGINEERING   CHEMISTRY 


637 


platinum  wires,  whereby  the  methane  is  burned  to  COg.  The 
half  of  the  contraction  here  found  upon  measurement  corresponds 
to  the  quantity  of  methane,  determined  by  passing  the  gas  into 
pipette  I,  to  absorb  the  COg  formed. 

The  residual  is  nitrogen. 

The  analysis  made  by  the  Orsat  apparatus  is  volumetric ;  if  the 
analysis  by  weight  is  required,  it  can  be  found  from  the  volu- 
metric analysis  as  follows : 

Multiply  the  percentages  by  volume  iby  either  the  densities  or 
the  molecular  weight  of  each  gas,  and  divide  the  products  by  the 
sum  of  all  the  products;  the  quotients  will  be  the  percentages  by 
weight.  For  most  work  sufficient  accuracy  is  secured  by  using 
the  even  values  of  the  molecular  weights. 

The  even  values  of  the  molecular  weights  of  the  gases  appear- 
ing in  an  analysis  by  an  Orsat  are : 

Carbon  dioxide   . ._ 44 

Carbon  monoxide   28 

Oxygen   32 

Nitrogen     28 

Table  i  mdicates  the  method  of  converting  a  volumetric  flue- 
gas  analysis  into  an  analysis  by  weight. 

TABLE  I.— Conversion  of  a  Fi^ue  Gas  Anai^ysis  By  Voi^ume 
To  One  By  Weight. 


Gas 

Analysis 

by  volume 

per  cent. 

Molecular 
weight 

Volume  times 

molecular 

weight 

Analysis 
by  weight 
per  cent. 

Carbon  Dioxide  CO.^ 
Carbon  Monoxide  CO 
Oxygen                      O 

Nitrogen                    N 

12.2 
0.4 
6.9 

80.5 

I2-|-(2  X  16) 

12  -h  16 

2x16 

2X  14 

536.8 

II. 2 

220.8 

2254.0 

536.8 
3022.8=17.7 

11.2 
3022.8=     0.4 
220.8 

3022.8=  7-3 
2254.0 

3022.8=74-0 

Total -.. 

loo.o 

3022.8 

100. 0 

Several  instruments  have  been  devised  to  indicate  continu- 
ously the  COo  and  also  to  record  the  same,  so  that  the  fireman 
shall  at  all  times  be  able  to  see  what  he  is  doing  in  the  way  of 


638 


ENGINEERING    CHEMISTRY 


efficient  firing,  and  the  superintendent  or  chief  engineer  have  a 
continuous  record  of  what  he  did,  and  thus  have  a  controlUng 
check  on  the  fireman's  work. 

To  obtain  these  continuous  records  the  usual  type  of  circular 
chart  driven  by  clockwork  is  almost  universally  employed,  the 
recording  pen  being  actutated  by  one  of  two  general  methods  (a) 
The  continuous  sample  method;  (b)  the  intermittent  sample 
method. 

(a)  The  action  of  the  continuous  sample  method  is  based  on 
the  law  governing  the  flow  of  gas  through  two  small  apertures. 
This  law  may  be  illustrated  by  a  simple  diagram  Fig.  123  repre- 


Fig.  123. 

senting  two  chambers  C  and  C^  which  are  in  communication  with 
each  other  through  the  aperture  A.  O  is  connected  with  an  as- 
pirator D,  as  shown.  The  manometers  p  and  q  indicate  the  gas 
tension  within  the  respective  chambers. 

When  the  aspirator  is  set  in  motion,  a  vacuum  is  created  in 
chamber  C^,  the  gas  will  flow  from  the  chamber  C  through 
aperture  B  to  chamber  C^,  creating  a  vacimm  in  C  which  will 
cause  gas  to  enter  through  aperture  A,  thus  establishing  a  con- 
tinviovis  flow  of  gas  through  both  apertures. 

If  a  constant  vacuum  of  say  48"  of  water  be  maintained  in 
chamber  C^  and  the  two  apertures  A  and  B  are  of  the  same  size 
and  are  maintained  at  the  same  temperature,  the  manometer  p 


ENGINEIERING    CHEMISTRY  639 

will  show  about  ^  the  vactium  maintained  in  C^,  due  to  the 
fact  that  the  apertures  offer  equal  resistance  to  the  passage  of 
the  gas.  This  relation  will  be  maintained  so  long  as  the  same 
volume  of  gas  flows  through  B  that  enters  at  A.  If,  however,  a 
constituent  of  gas  be  continuously  taken  away  or  absorbed  from 
the  gas  in  passing  through  chamber  C,  the  vacuum  therein  will 
be  correspondingly  increased.  This  increase  of  vacuum  in  C, 
shown  by  the  manometer  p,  therefore  correctly  indicates  the  vol- 
ume of  gas  absorbed  and  this  is  utilized  in  practice  to  indicate 
the  percentages  of  CO2  in  the  flue  gas. 

To  utilize  this  principle  in  a  practical  apparatus,  the  following 
condition  must  be  fulfilled. 

(i)  The  gas  must  be  brought  to  the  instrument  under  a  con- 
stant tension  and  must  be  drawn  through  the  aperture  with  a 
continuous  and  uniform  suction. 

(2)  Both  apertures  must  be  located  in  a  medium  of  constant 
temperatures. 

(3)  Provision  must  be  made  that  the  aperture  remain  per- 
fectly clean. 

(4)  The  chamber  C  must  be  made  perfectly  tight  so  that  no 
gas  can  enter,  except  through  aperture  A. 

(5)  The  CO2  to  be  measured  must  be  completely  absorbed 
after  the  gas  passes  through  A,  and  before  it  passes  through  B. 

In  spite  of  the  care  required  to  secure  satisfactory  results  with 
this  type  of  CO2  recorder  it  possesses  one  big  advantage  over  all 
other  types  in  that  it  gives  a  continuous  indication  of  the  amount 
of  CO2  in  the  gases. 

{h)    Intermittent  Sample  Method. 

In  obtaining  CO2  records  by  this  method  measured  samples  of 
the  gas  are  drawn  into  the  apparatus,  the  CO2  absorbed  as  in  an 
Orsat  or  Hempel  machine,  the  new  volume  of  the  gas  measured 
and  the  result  recorded  on  the  chart.  In  other  words,  the  Inter- 
mittent Sample  Method  is  simply  an  automatic  Orsat,  which  at 
definite  intervals,  takes  a  sample  of  the  gas,  automatically  deter- 
mines the  percentage  of  CO2  and  then  records  it,  the  whole  op- 
eration taking  from  5  to  10  minutes  for  each  sample.  In  this 
case  the  recording  pen  remains  fixed  during  a  time  interval  equal 


640  Engine:ering  chemistry 

to  that  required  to  make  a  complete  analysis, — moving  radially 
along  the  chart  to  a  new  position  as  soon  as  the  analysis  of  the 
new  gas  sample  has  been  completed.  This  gives  a  curve  made 
up  of  a  series  of  broken  lines  which  does  not  truly  represent  a 
"continuous"  CO2  analysis,  but  due  to  the  simplicity  of  operation 
of  this  type,  it  is  tinding  wide  use  in  boiler  room  practice,  where 
an  approximate  average  value  of  the  COo  is  all  that  is  desired. 

These  recording  types  of  CO^  machines,  while  originally  de- 
signed for  use  with  flue  gases,  may  be  adapted  to  a  wide  variety 
of  gases  in  the  different  arts  by  changing  the  absorbing  solution 
to  receive  any  desired  gas  instead  of  CO^. 

An  extremely  simple  method  of  obtaining  an  average  value  of 
a  "continuous"  flue  gas  sample  is  to  take  two  large  bottles,  the 
upper  filled  with  water  and  so  connected  with  the  lower  by  rub- 
ber tubing  that  the  water  will  flow  from  the  upper  to  the  lower 
by  gravity  and  at  any  desired  rate  by  means  of  regulating  pinch 
cocks.  The  upper  bottle  is  connected  with  a  sampling  pipe  lead- 
ing to  the  flue  so  that  as  the  water  runs  out  of  the  bottom  of  the 
bottle,  the  flue  gas  is  drawn  in  at  the  top  to  replace  it.  This  may 
be  set  so  that  the  sample  will  cover  several  hours,  at  the  end  of 
which  time  all  openings  to  the  upper  bottle  are  closed,  and  the 
sample  taken  up  to  the  laboratory  to  be  analyzed  in  either  a 
Hempel  or  Orsat  machine.  In  using  this  two-bottle  combination, 
great  care  must  be  exercised  to  be  sure  that  all  joints  are  per- 
fectly tight,  as  a  very  slight  air  leak  in  any  part  will  have  a  very 
decided  effect  on  the  CO2  obtained.  Also  the  water  must  be 
thoroughly  saturated  so  that  it  will  not  take  up  any  of  the  CO^ 
from  the  gas. 

Although  these  automatic  or  continuous  COo  machines  are  ex- 
cellent for  regular  power  plant  work,  when  determinations  are 
desired  in  boiler  test  work,  the  Orsat  style  of  apparatus  is  still 
in  favor,  due  to  its  ability  to  give  not  only  the  COo  accurately 
whenever  desired,  but  also  to  determine  the  percentage  .of  oxygen 
and  carbon  monoxide,  a  knowledge  of  the  proportions  of  both 
of  which  in  the  flue  gas  is  necessary  for  the  testing  engineer  in 
working  up  his  results.     To  indicate  the  value  of  the  flue  gas 


ENGINEERING   CHEMISTRY 


641 


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642  ENGINEERING    CHEAITSTRY 

analyses  in  boiler  operation,  the  following  extract  from  the  35th 
Edition  of  ''Steam"  is  given: 

Each  combustible  element  of  a  fuel  will  combine  with  oxygen 
in  certain  definite  proportions  and  will  generate  a  definite  amount 
of  heat,  measured  in  B.  t.  u.  This  definite  amount  of  heat  per 
pound  liberated  by  perfect  combustion  is  termed  the  calorific 
value  of  that  substance.  Table  2  gives  certain  data  on  the 
reactions  and  results  of  combustion  for  elementary  combustibles 
and    several   compounds. 

It  w411  be  seen  from  this  table  that  a  pound  of  carbon  will 
unite  with  2%  pounds  of  oxygen  to  form  carbon  dioxide,  and 
will  evolve  I4,6(X)  B.  t.  u.  As  an  intermediate  step,  a  pound  of 
carbon  may  unite  with  ly^  pounds  of  oxygen  to  form  carbon 
monoxide  and  evolve  4,450  B.  t.  u.,  but  in  its  further  conversion 
to  CO2  it  would  unite  with  an  additional  lys  times  its  weight  of 
oxygen  and  evolve  the  remaining  10,150  B.  t.  u.  When  a  pound 
of  CO  burns  to  CO2,  however,  only  4,350  B.  t.  u.  are  evolved 
since  the  pound  of  CO  contains  but  "/-  pounds  carbon. 

Air  required  for  Combustion. — It  has  already  been  shown  that 
each  combustible  element  in  fuel  will  unite  with  a  definite  amount 
of  oxygen.  With  the  ultimate  analysis  of  the  fuel  known,  in 
connection  with  Table  2,  the  theoretical  amount  of  air  required 
may  be  readily  calculated. 

Let  the  ultimate  analysis  be  as  follows : 

Per  cent. 

Carbon 7479 

Hydrogen    4.98 

Oxygen    6.42 

Nitrogen    i .20 

Sulphur    3.24 

Water    1.55 

Ash    7.82 

Total   100.00 

When  complete  combustion  takes  place,  as  already  pointed  out, 
the  carbon  in  the  fuel  unites  with  a  definite  amount  of  oxygen  to 
form  CO2.  The  hydrogen,  either  in  a  free  or  combined  state, 
will  unite  with  oxygen  to  form  water  vapor,  H^O.     Not  all  of 


e:ngine:e:ring  che:mistry  643 

the  hydrogen  shown  in  a  fuel  analysis,  however,  is  available  for 
the  production  of  heat,  as  a  portion  of  it  is  already  united  with 
the  oxygen  shown  by  the  analysis  in  the  form  of  water,  H^O. 
Since  the  atomic  weights  of  H  and  O  are  respectively  i  and 
16,  the  weight  of  the  combined  hydrogen  will  be  j4,  of  the 
weight  of  the  oxygen,  and  the  hydrogen  available  for  combustion 
will  be  —  /^  O.  In  complete  combustion  of  the  sulphur,  sul- 
phur dioxide  SO2  is  formed. 

Expressed  numerically,  the  theoretical  amount  of  air  for  the 
above  analysis  is  as  follows : 

0.7479  C  X  2^  =  1.9944  O  needed 

0.0642 


f  0.0498 


H  X  8  =  0.3262  O  needed 


0.324  S  X  I  =  0.0324  O  needed 

Total     2.3530  O  needed 

One  pound  of  oxygen  is  contained  in  4.32  pounds  of  air. 

The  total  air  needed  per  pound  of  coal,  therefore,  will  be  2.353 
X  4.32  =  10.165. 

The  weight  of  combustible  per  pound  of  fuel  is  0.7479  -f" 
0.0418^  -f-  0.0324  -j-  0.012  =  0.83  pound,  and  the  air  theoretic- 
ally required  per  pound  of  combustible  is  10.165  -^  0.83  =  12.2 
pounds. 

The  above  is  equivalent  to  computing  the  theoretical  amount 
of  air  required  per  pound  of  fuel  by  the  formula: 

Weight  per  pound  =  11.52  C  +  34.56  (h -j-^  4-35  S(io) 

where  C,  H,  O  and  S  are  proportional  parts  by  weight  of  carbon, 
hydrogen,  oxygen  and  sulphur  by  ultimate  analysis. 

In  practice  it  is  impossible  to  obtain  perfect  combustion  with 
the  theoretical  amount  of  air,  and  an  excess  may  be  required, 
amounting  to  sometimes  double  the  theoretical  supply,  depending 
upon  the  nature  of  the  fuel  to  be  burned  and  the  method  of 
burning  it.  The  reason  for  this  is  that  it  is  impossible  to  bring 
each  particle  of  oxygen  in  the  air  into  intimate  contact  with  the 
particles  in  the  fuel  that  are  to  be  oxidized,  due  not  only  to  the 

1  Available  hydrogen. 


644  i;ngine;e;ring  chemistry 

dilution  of  the  oxygen  in  the  air  by  nitrogen,  but  because  of  such 
factors  as  the  irregular  thickness  of  the  fire,  the  varying  resist- 
ance to  the  passage  of  the  air  through  the  fire  in  separate  parts 
on  account  of  ash,  clinker,  etc.  Where  the  difficulties  of  draw- 
ing air  uniformly  through  a  fuel  bed  are  eliminated,  as  in  the 
case  of  burning  oil  fuel  or  gas,  the  air  supply  may  be  materially 
less  than  would  be  required  for  coal.  Experiment  has  shown 
that  coal  wall  usually  require  50  per  cent,  more  than  the  theoret- 
ical net  calculated  amount  of  air,  or  about  18  pounds  per  pound 
of  fuel  either  under  natural  for  forced  draft,  though  this  amount 
may  vary  widely  with  the  type  of  furnace,  the  nature  of  the  coal, 
and  the  method  of  firing.  If  less  than  this  amount  of  air  is  sup- 
plied, the  carbon  burns  to  monoxide  instead  of  dioxide  and  its 
full  heat  value  is  not  developed. 

An  excess  of  air  is  also  a  source  of  waste,  as  the  products  of 
combustion  will  be  diluted  and  will  carry  off  an  excessive  amount 
of  heat  in  the  chimney  gases,  or  the  air  will  so  lower  the  tefnpera- 
ture  of  the  furnace  gases  as  to  delay  the  combustion  to  an  ex- 
tent that  will  cause  carbon  monoxide  to  pass  off  unburned  from 
the  furnace.  A  sufficient  amount  of  carbon  monoxide  in  the  gases 
may  cause  the  action  known  as  secondary  combustion,  by  igniting 
or  mingling  with  air  after  leaving  the  furnace  or  in  the  flues  or 
stack.  Such  secondary  combustion,  which  takes  place  either 
within  the  setting  after  leaving  the  furnace,  or  in  the  flues  or 
•stack  always  leads  to  a  loss  of  efficiency  and,  in  some  cases,  to 
overheating  of  the  flues  and  stack. 

Table  3  gives  the  theoretical  amount  of  air  required  for  va- 
rious fuels  calculated  from  formula  {10)  assuming  the  analyses 
of  the  fuels  given  in  the  table. 

The  object  of  a  flue  gas  analysis  is  the  determination  of  the 
completeness  of  the  combustion  of  the  carbon  in  the  fuel,  and  the 
amount  and  distribution  of  the  heat  losses  due  to  incomplete 
combustion.  The  quantities  actually  determined  by  an  analysis 
are  the  relative  proportions  by  volume,  of  carbon  dioxide  (CO2), 
oxygen  (O),  and  carbon  monoxide  (CO),  the  determinations 
being  made  in  this  order. 


e:nginee)ring  chemistry 


645 


TABLE  3. — CATXUI.ATED  Theoreticai,  Amount  oe  Air  Required  per 
Pound  of  Various  Fuei.s. 


Fuel 


Weight  of  constituents  in  one 
pound  dry  fuel 


Carbon 
per  cent. 


Hydrogen 
per  cent. 


Oxygen 
per  cent. 


Air  Required 

per  pound 

of  fuel 

Pounds 


Coke 

Anthracite  Coal  • . 
Bituminuous  Coal 

Lignite 

Wood 

Oil 


94.0 

91-5 
87.0 
70,0 

50.0 
85.0 


3-5 
5.0 
5.0 
6.0 
13.0 


2.6 

4.0 

20.0 

43-5 
i.o 


10.8 

II. 7 

II. 6 

8.9 

6.0 

14.3 


The  variations  of  the  percentages  of  these  gases  in  an  analysis 
is  best  illustrated  in  the  consideration  of  the  complete  combustion 
of  pure  carbon,  a  pound  of  which  requires  2.67  pounds  of  oxy- 
gen/ or  32  cu.  ft.  at  60°  F.  The  gaseous  product  of  such  com- 
bustion will  occupy,  when  cooled,  the  same  volume  as  the  oxy- 
gen, namely  32  cu.  ft.  The  air  supplied  for  the  combustion  is 
made  up  of  20.91  per  cent,  oxygen  and  79.09  per  cent,  nitrogen 
by  volume.  The  carbon  united  with  the  oxygen  in  the  form  of 
carbon  dioxide  will  have  the  same  volume  as  the  oxygen  in  the 
air  originally  supplied.  The  volume  of  the  nitrogen  when  cooled 
will  be  the  same  as  in  the  air  supplied,  as  it  undergoes  no  change. 
Hence  for  complete  combustion  of  one  pound  of  carbon,  where 
no  excess  of  air  is  supplied,  an  analysis  of  the  products  of  com- 
bustion will  show  the  following  percentages  by  volume : 

Actual  volume 
for  one  pound  carbon         Per  cent, 
cubic  feet  by  volume 

Carbon  dioxide  32        =  20.91 

Oxj^gen    o        —  0.00 

Nitrogen    121         =  79.09 

Air  required  for  one  pound  carbon 153  100.00 

For  50  per  cent,  excess  air  the  volume  will  be  a  follows : 
153  X  i>^  =  229.5  cu.  ft.  of  air  per  pound  of  carbon. 

1  See  Table  2,  p.  641. 


646  Engine:e:ring  CHICMISTRY 

Actual  volume 
for  one  pound  carbon         Per  cent, 
cubic  feet  by  volume 

Carbon  dioxide 32  =  13.01  (  _  20.91  per  cent. 

Oxygen 16  =  7-oo  ^  ^ 

Nitrogen.    181. 5        =  79.09 

229.5  100.00 

For  100  per  cent,  excess  air  volume  will  be  as  follows : 
153  X  2  =  306  cu.  ft.  of  air  per  pound  of  carbon. 

Actual  volnme 
for  one  pound  carbon  Per  cent, 

cubic  feet  by  volume 

Carbon  dioxide 32  =  io-45  |  _  ^0.91  per  cent. 

Oxygen 32  =  10.45  )  ^    ^ 

Nitrogen 242  =  79-09 

306  100.00 

In  each  case  the  volume  of  oxygen  which  combines  with  the 
carbon  is  equal  to  (cubic  feet  of  air  X  20,91  per  cent.) — 32  cubic 
feet. 

It  will  be  seen  that  no  matter  what  the  excess  of  air  supplied, 
the  actual  amount  of  carbon  dioxide  per  pound  of  carbon  re- 
mains the  same,  while  the  percentage  by  volume  decreases  as  the 
excess  of  air  increases.  The  actual  volume  of  oxygen  and  the 
percentage  by  volume  increases  with  the  excess  of  air,  and  the 
percentage  of  oxygen  is,  therefore,  an  indication  of  the  amount 
of  excess  air.  In  each  case  the  sum  of  the  percentages  of  CO^, 
and  O  is  the  same,  20.9.  Although  the  volume  of  nitrogen  in- 
creases with  the  excess  of  air,  its  percentage  by  volume  remains 
the  same  as  it  undergoes  no  change  while  combustion  takes  place  ; 
its  percentage  for  any  amount  of  air  excess,  therefore,  will  be 
the  same  after  combustion  as  before,  if  cooled  to  the  same  tem- 
perature. It  must  be  borne  in  mind  that  the  above  conditions 
hold  only  for  the  perfect  combustion  of  a  pound  of  pure  carbon. 

Carbon  monoxide  (CO)  produced  by  the  imperfect  combus- 
tion of  carbon,  will  occupy  twice  the  volume  of  oxygen  entering 
into  its  composition  and  will  increase  the  volume  of  the  flue  gases 
over  that  of  the  air  supplied  for  combustion  in  the  proportion  of 

100  +  )4  the  per  cent,  of  CO 
100 


ENGINEEJRING    CHEMISTRY  647 

When  pure  carbon  is  the  fuel,  the  sum  of  the  percentages  by 
volume  of  carbon  dioxide,  oxygen  and  ^  of  the  carbon  monox- 
ide, must  be  in  the  same  ratio  to  the  nitrogen  in  the  flue  gases 
as  is  the  oxygen  to  the  nitrogen  in  the  air  supplied,  that  is,  20.91 
to  79.09.  When  burning  coal,  however,  the  percentage  of  nitro- 
gen is  obtained  by  subtracting  the  sum  of  the  percentages  by 
volume  of  the  other  gases  from  100.  Thus  if  an  analysis  shows 
12.5  per  cent.  CO2,  6.5  per  cent.  O,  and  0.6  per  cent.  CO,  the 
percentage  of  nitrogen  which  ordinarily  is  the  only  other  con- 
stituent of  the  gas  which  need  be  considered,  is  found  as  follows : 

100  —  (12.5  +  6.5  +  0.6)  =  80.4  per  cent. 

The  action  of  the  hydrogen  in  the  volatile  constituents  of  the 
fuel  is  to  increase  the  apparent  percentage  of  the  nitrogen  in  the 
flue  gases.  This  is  due  to  the  fact  that  the  water  vapor  formed 
by  the  combustion  of  the  hydrogen  will  condense  at  a  temj^^ra- 
ture  at  which  the  analysis  is  made,  while  the  nitrogen  which  ac- 
companied the  oxygen  with  which  the  hydrogen  originally  com- 
bined maintains  its  gaseous  form  and  passes  into  the  sampling 
apparatus  with  the  other  gases.  For  this  reason  coals  contain- 
ing high  percentages  of  volatile  matter  will  produce  a  larger 
quantity  of  water  vapor,  and  thus  increase  the  apparent  percent- 
age of  nitrogen. 

Air  Required  and  Supplied. — When  the  ultimate  analysis  of 
a  fuel  is  known,  the  air  required  for  complete  combustion  with 
no  excess  can  be  found  as  shown  in  the  chapter  on  combustion, 
or  from  the  following  approximate  formula : 

Pounds  of  air  required  per  pound  of  fuel  = 

where  C,  H  and  O  equal  the  percentage  by  weight  of  carbon, 
hydrogen  and  oxygen  in  the  fuel  divided  by  100. 

When  the  flue  gas  analysis  is  known,  the  total  amount  of  air 
supplied  is : 

*  This  formula  is  equivalent  to  (lo)  given  in  above.  34-56  =  theoretical  air  required 
for  combustion  of  one  pound  of  H  (see  Table  2). 


648  ENGINEI^RING    CHEMISTRY 

Pounds  of  air  supplied  per  pound  of  fuel  = 

3.036  (^o;L)xC.  (:.) 

where  N,  CO2  and  CO  are  the  percentages  by  volume  of  nitrogen, 
carbon  dioxide  and  carbon  monoxide  in  the  flue  gases,  and  C  the 
percentage  by  weight  of  carbon  which  is  burned  from  the  fuel 
and  passes  up  the  stack  as  flue  gas.  This  percentage  of  C  which 
is  burned  must  be  distinguished  from  the  percentage  of  C  as 
found  by  an  ultimate  analysis  of  the  fuel.  To  find  the  percentage 
of  C  which  is  burned,  deduct  from  the  total  percentage  of  carbon 
as  found  in  the  ultimate  analysis,  the  percentage  of  unconsumed 
carbon  found  in  the  ash.  This  latter  quantity  is  the  dift'erence 
between  the  percentage  of  ash  found  by  an  analysis  and  that  as 
determined  by  a  boiler  test.  It  is  usually  assumed  that  the  entire 
combustible  element  in  the  ash  is  carbon,  which  assumption  is 
practically  correct.  Thus  if  the  ash  in  a  boiler  test  were  16  per 
cent,  and  by  analysis  contained  25  per  cent,  of  carbon,  the 
percentage  of  unconsumed  carbon  would  be  16  X  -25  =  4  per 
cent,  of  the  total  coal  burned.  If  the  coal  contained  by  ultimate 
analysis  80  per  cent,  of  cabon  the  percentage  burned,  and  of 
which  the  products  of  combustion  pass  up  the  chimney  would  be 
80  —  4  ^^  76  per  cent.,  which  is  the  correct  figure  to  use  in  cal- 
culating the  total  amount  of  air  supplied  by  formula  (/^). 

The  weight  of  flue  gases  resulting  from  the  combustion  of  a 
pound  of  dry  coal  will  be  the  sum  of  the  weights  of  the  air  per 
pound  of  coal  and  the  combustible  per  pound  of  coal,  the  latter 
being  equal  to  one  minus  the  percentage  of  ash  as  found  in  the 
boiler  test.  The  weight  of  flue  gases  per  pound  of  dry  fuel  may, 
however,  be  computed  directly  from  the  analyses,  as  shown  later, 
and  the  direct  computation  is  that  ordinarily  used. 

The  ratio  of  the  air  actually  supplied  per  pound  of  fuel  to  that 
theoretically  required  to  burn  it  is : 

'"''(.  CO.  +  CO  )  '^  '^  ,,3, 

*  For  degree  of  accuracy  of  this  formula,  see  Transactions,  A.  .S  M.  E  ,  Volume  XXI, 
1900,  page  94. 


ENGINEERING   CHEMISTRY 


649 


in  which  the  letters  have  the  same  significance  as  in  formulae 
(//)  and  (12). 

The  ratio  of  the  air  supplied  per  pound  of  combustible  to  the 
amount  theoretically  required  is : 

N 


CO) 


(14) 


N  — 3.782  (O  - 
which  is  derived  as  follows : 

The  N  in  the  flue  gas  is  the  content  of  nitrogen  in  the  whole 
amount  of  air  supplied.  The  oxygen  in  the  flue  gas  is  that  con- 
tained in  the  air  supplied  and  which  was  not  utilized  in  com- 
bustion. The  oxygen  was  accompanied  by  3.782  times  its  volume 
of  nitrogen.    The  total  amount  of  excess  oxygen  in  the  flue  gases 


is  (O 


14 


CO)  ;  hence  N  —  3.782  (O  —  ^/^  CO)  represents  the 


nitrogen  content  in  the  air  actually  required  for  combustion  and 
N  ^  (N  —  3.782  [O  —  ^  CO] )  is  the  ratio  of  the  air  supplied 
to  that  required.  This  ratio  minus  one  will  be  the  proportion  of 
excess  air. 

The  heat  lost  in  the  flue  gases  is 

I.  Z.Z0.24W  (T-0  (15) 

Where  L  =  B.  t.  u.  lost  per  pound  of  fuel, 

W  =  weight  of  flue  gases  in  pounds  per  pound  of  dry 

coal, 
T  =:  temperature  of  flue  gases, 
t  =  temperature  of  atmosphere, 
0.24  =  specific  heat  of  the  flue  gases. 
The  weight  of  flue  gases,  W,  per  pound  of  carbon  can  be  com- 
puted directly  from  the  flue  gas  analysis  from  the  formula : 

ir  CO,  -f  80+  7(CO  +  N)  . 

3  (CO,  -h  CO) 

where  CO^,  O,  CO,  and  N  are  the  percentages  by  volume  as  de- 
termined by  the  flue  gas  analysis  of  carbon  dioxide,  oxygen,  car- 
bon monoxide  and  nitrogen. 

The  weight  of  flue  gas  per  pound  of  dry  coal  will  be  the 
weight  determined  by  this  formula  multiplied  by  the  percentage 
of  carbon  in  the  coal  from  an  ultimate  analysis. 


650 


ENGINKE)RING    CHEMISTRY 


:;i::|i;;jig»i:j[j[|[i^u|iS:jp:g?:i|^ 


o 


.•=!» 

^ii 

stn 

0  „ 

-C-" 

4;   l; 

nd 

P9  K 

<u 

0 

l>  0 

-O  != 

^ 

>< 

c: 

0  s 

R 

?^ 

0 

Is 

s    ■ 

0 

0  -^ 

Tl 

o?i 

rt 

-1 

5^  ^- 

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hr^ 

Ph 

c  "^ 

r  "^ 

^ 

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:d 

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5P&> 

M 

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^ 

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►^ 

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(I) 

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a 

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*  For  loss  per  pound  of  coal  multiply  by  per  cent,   of  carbon   in   coal   bj'   ultimate 
analysis. 


^NGIN^^RING   CHEMISTRY  65 1 

Fig.  124  represents  graphically  the  loss  due  to  heat  carried  away 
by  dry  chimney  gases  for  varying  percentages  of  CO,,  and  dif- 
ferent temperatures  of  exit  gases. 


8  8  8  8 


The  heat  lost,  due  to  the  fact  that  the  carbon  in  the  fuel  is 


652  ENGINEE^RING   CHEMISTRY 

not  completely  burned  and  carbon  monoxide  is  present  in  the  flue 
gases,  in  B.  t.  u.  per  pound  of  fuel  burned  is : 

L=.o,:5ox(cO^°CoJc  (17) 

where,  as  before,  CO  and  CO,  are  the  percentages  by  volume  in 
the  flue  gases  and  C  is  the  proportion  by  weight  of  carbon  which 
is  burned  and  passes  up  the  stack. 

Fig.  125  represents  graphically  the  loss  due  to  such  carbon  in 
the  fuel  as  is  not  completely  burned  but  escapes  up  the  stack  in 
the  form  of  carbon  monoxide. 

Application  of  Formulae  and  Rules. — Pocahontas  coal  is 
burned  in  the  furnace,  a  partial  ultimate  analysis  being: 

Per  cent. 

Carbon    82.1 

Hydrogen    4.25 

Oxygen    2.6 

Sulphur   1.6 

Ash    6.0 

B.  t.  u.,  per  pound  dry 14,500 

The  flue  gas  analysis  shows : 

Per  cent. 
CO2     107 

O    90 

CO 0.0 

N    (by  difference) 80.3 

Determine:  The  flue  gas  analysis  by  weight  (see  Table  i), 
the  amount  of  air  required  for  perfect  combustion,  the  actual 
weight  of  air  per  pound  of  fuel,  the  weight  of  flue  gas  per  pound 
of  coal,  the  heat  lost  in  the  chimney  gases  if  the  temperature  of 
these  is  500°  F.,  and  the  ratio  of  the  air  supplied  to  that  theor- 
etically required. 

Solution:  The  theoretical  weight  of  air  required  for  perfect 
combustion,  per  pound  of  fuel,  from  formula  (//)  will  be, 

^  /0.821     ,     .                   0.026          o.oi6\ 
W  =  34  56  (— h  (0.0425 ^)  H ^  j  =  10.88  lbs. 

If  the  amount  of  carbon  which  is  burned  and  passes  away  as 
flue  gas  is  80  per  cent.,  which  would  allow  for  2.1  per  cent,  of 


e)ngine:e:ring  chemistry 


653 


unburned  carbon  in  terms  of  the  total  weight  of  dry  fuel  burned, 
the  weight  of  dry  gas  per  pound  of  carbon  burned  will  be  from 
formula  (16)  : 


W  = 


1 1  X  10.7  -I-  8  X  9.0  +  7  (o  4-  80.3) 


=  23.42  pounds 


3  C10.7  +  o; 

and  the  weight  of  flue  gas  per  pound  of  coal  burned  will  be  0.80 
X  23.42  =  18.74  pounds. 

The  heat  lost  in  the  flue  gases  per  pound  of  coal  burned  will 
be  from  formula  (6)  and  the  value  18.74  just  determined. 

Loss  =  0.24  X"  18.74  X  (500  —  60)  =:  1979  B.  t.  u. 

The  percentage  of  heat  lost  in  the  flue  gases  will  be  1979  -^ 
14,500  =13.6  per  cent. 

The  ratio  of  air  supplied  per  pound  of  coal  to  that  theoretically 
required  will  be  18.74  -f-  10.88  ^=  1.72  per  cent. 

The  ratio  of  air  supplied  per  pound  of  combustible  to  that  re- 
quired will  be  from  formula  (14)  : 

0.803 _ 

0.803  —  3.782  (0.09— >^  X  o)  ~  ^'^^ 

The  ratio  based  on  combustible  will  be  greater  than  the  ratio 
based  on  fuel  if  there  is  unconsumed  carbon  in  the  ash. 

Unreliability  of  CO^  Readings  Taken  Alone. — It  is  generally 
assumed  that  high  CO2  readings  are  indicative  of  good  combus- 
tion and  hence  of  high  efficiency.  This  is  true  only  in  the  sense 
that  such  high  readings  do  indicate  the  small  amount  of  excess 
air  that  usually  accompanies  good  combustion,  and  for  this 
reason  high  CO2  readings  alone  are  not  considered  entirely  re- 
liable. Wherever  an  automatic  CO^  recorder  is  used,  it  should 
be  checked  from  time  to  time  and  the  analysis  carried  further 
with  a  view  to  ascertaining  whether  there  is  CO  present.  As  the 
percentage  of  CO2  in  these  gases  increases,  there  is  a  tendency 
toward  the  presence  of  CO,  which,  of  course,  cannot  be  shown  by 
a  CO2  recorder,  and  which  is  often  difficult  to  detect  with  an  Or- 
sat  apparatus.  The  greatest  care  should  be  taken  in  preparing 
the  cuprous  chloride  solution  in  making  analyses  and  must  be 
known  to  be  fresh  and  capable  of  absorbing  CO.     In  one  in- 


654 


e:ngine:e:ring  chemistry 


stance  that  came  to  our  attention,  in  using  an  Orsat  apparatus 
where  the  cuprous  chloride  solution  was  believed  to  be  fresh,  no 
"CO  was  indicated  in  the  flue  gases  but  on  passing  the  same 
sample  into  a  Hempel  apparatus,  a  considerable  percentage 
was  found.  It  is  not  safe,  therefore,  to  assume  without  question 
from  a  high  CO^  reading  that  the  combustion  is  correspondingly 
good,  and  the  question  of  excess  air  alone  shall  be  distinguished 
from  that  of  good  combustion.  The  effect  of  a  small  quantity  of 
CO,  say  I  per  cent.,  present  in  the  flue  gases  will  have  a  negli- 
gible influence  on  the  quantity  of  excess  air,  but  the  presence  of 
such  an  amount  would  mean  a  loss  due  to  the  incomplete  com- 
bustion of  the  carbon  in  the  fuel  of  possibly  4.5  per  cent,  of  the 
total  heat  in  the  fuel  burned.  When  this  is  considered,  the  im- 
portance of  a  complete  flue  gas  analysis  is  apparent. 

Table  4  gives  the  densities  of  various  gases    together    with 
other  data  that  will  be  of  service  in  gas  analysis  work. 


TABLE  4. — Density  of  Gases  at  32  Degrees  Fahrenheit 
AND  Atmospheric  Pressure. 

Adapted  from  Smithsonian  tables. 


Gas 

Chemi- 
cal 
symbol 

Specific 
gravity 
Air  =  I 

Weight  of 
one  cubic 

foot 
pounds 

Volume  of 
one  pound 
cubic  feet 

Relative 
hydro{ 

Exact 

density, 
yen  =  i 

Approxi- 
mate 

0 

N 

H 

CO, 

CO 

CH, 

C,He 

SO2 

1.053 

0.9673 

0.0696 

1. 5291 

0.9672 

0.5576 

1.075 
0.920 
2.2639 
1. 0000 

.08922 

.07829 

.005621 

.12269 

.07807 

.04470 

.08379 

.07254 

.17862 

.08071 

11.208 

12.773 
177.90 

8.151 
12.809 
22.371 
11.935 
13.785 

5.59« 
12.390 

15.87 
13.92 

1. 00 
21.83 
13.89 

7.95 
14.91 
12.91 
31.96 

16 

H 

I 

22 

14 

8 
15 
13 
32 

Nitrogen 

Hydrogen 

Carbon  dioxide  •  ■ . 
Carbon  monoxide- 
Methane 

Acetylene 

Sulphur  dioxide  - . 
Air 

ENGINEERING    CHEMISTRY 

ANALYSIS  OF  ILLUMINATING  GAS.^ 


655 


Description  and  Method  of  Operating  the  Standard 
U.  G.  I.  Gas  Analyzing  Apparatus. 

The   following  pipettes  and   reagents    are    required     for    the 
analysis:  (see  Figs.  126,  127,  128,  129.) 


I 


^ 

ik 

M   ; 

1^ 

1            f        1 

Fig.  126— This  cut  represents  a  complete  gas  analyzing  apparatus,  consisting  of  a 
standard  U.  G.  I.  Hempel  burette,  pipette  stands,  six  pipettes,  induction  coil  and 
battery. 


The  burette  as  seen  in  Fig.  130  is  similar  to  that  described  in 
Hempel's  Gas  Analysis  on  page  28,  except  that  a  four-way  cock 
C  replaces  the  three-way  cock  used  by  Hempel  and  the  burette 
is  bulbed,  thereby  shortening  the  same  and  allowing  a  finer 
graduation. 


'  The  above  article  is  here  published  through  the  kindness  of   Mr.   W.  H.  Fulwtiler, 
Chemist,  The  United  Gas  Improvement  Company,  Philadelphia,  Pa. 


Fig.  127.— Standard  U.  G.  I.  Hempel  burette.  A  .special  feature  of  this  burette  is  the 
four-way  stop-cock,  which  permits  a  permanent  connection  with  the  potash  pipette,  thus 
obviating  the  necessity  of  repeatedly  connecting  and  disconnecting  the  pipette  duri^ng 
the  course  of  an  analy.sis. 


I 


ENGINK^RING   CHEMISTRY 


657 


Fig.  128.— Double-absorption  cuprous  chloride  pipette.  This  is  designed  to  replace 
the  two  double-absorption  pipettes  otherwise  necessary  in  making  a  gas  analysis.  By 
simply  turning  the  cock,  it  is  possible  to  bring  the  gas  in  contact  with  the  absorbent 
contained  in  either  side  of  the  pipette  without  disconnecting.  Compactness,  and  ease  of 
filling  and  operation  are  the  special  features  of  this  pipette. 


42 


658 


Knginke:ring  chkmistry 


Fig.  129.— Tutwiler  and  Bond  hygrometer.  This  instrument  indicates  the  tempera- 
ture point  of  saturation  of  a  gas  with  hydrocarbon  vapor  or  with  water  vapor  present  in 
the  gas  at  the  time  of  testing.  It  is  particularly  valuable  in  connection  with  the  mainten- 
ance of  a  uniform  quality  of  gas,  as  by  its  use  we  may  determine  the  lowest  temperature 
to  which  the  gas  subsequently  may  be  subjected  on  its  way  to  the  consumer,  without 
injury  to  its  heating  or  lighting  value. 


EJNGINKERING   CHEMISTRY  659 

The  capacity  of  the  burette  is  about  105  cc.  graduated  in  1/20 
cc.  from  40  cc.  to  102  cc.  It  is  connected  through  the  capillary 
tube  D  coming  out  from  the  back  of  the  cock  C  with  manometer 
tube  M.  The  manometer  is  connected  with  the  Petterson  cor- 
rection tube  R.  A  water  jacket  /  surrounds  the  Petterson  tube 
and  burette.  A  potash  absorption  pipette  K  which  rests  on  the 
adjustable  stand  S  is  connected  permanently  with  the  capillary 
tube  B. 

A  potash  absorption  pipette  which  is  permanently  attached  to 
the  burette  as  shown  in  the  sketch. 

A  pipette  filled  with  strong  bromine  water.  In  order  that  this 
solution  remain  concentrated  an  excess  of  free  bromine  is  kept 
in  the  pipette. 

A  pipette  for  solids  filled  with  stick  phosphorous  covered  with 
water. 

A  double  U.  G.  I  absorption  pipette.  This  combines  in  one 
piece  of  apparatus  the  two  solutions  of  cuprous  chloride  which 
are  necessay  to  remove  the  carbon  monoxide. 

A  simple  pipette  filled  with  saturated  water  for  storage  pur- 
poses. 

A  mercury  explosion  pipette. 

A  U-shaped  combustion  tube  containing  about  one-half  gram 
palladium  black  is  also  required. 

The  following  is  the  method  of  procedure  for  an  analysis  of 
a  gas  containing  CO2,  C^Hg;,,  Og,  H^OH^,  CgHg,  and  N^. 

Completely  fill  water  jacket  with  distilled  water. 

Turn  cock  C  so  that  the  interior  of  the  burette  Y  communi- 
cates with  A,  open  cock  Z,  raise  leveling  bulb  L,  which  has  been 
filled  with  gas  saturated  water,  until  water  flows  out  A.  Turn 
C  so  that  interior  of  burette  communicates  with  K,  and  draw 
over  potash  solution  to  just  above  cock  C. 

Turn  cock  C  so  that  Y  communicates  with  D  and,  by  raising 
and  lowering  L  and  allowing  air  to  escape  through  A,  fill  M 
with  water  to  A^.  Open  C  to  A  and,  by  lowering  L,  draw  in  air. 
Close  C,  raise  L,  open  C  to  D  and  admit  air  in  M  to  O,  and  close 
C. 


66o  ENGINEERING   CHEMISTRY 

Disconnect  M  momentarily  at  P  and  reconnect.  The  air  in  A 
is  now  at  atmospheric  pressure. 

Connect  the  tube  containing  gas  sample  with  A,  using  glass 
connector  similar  to  one  used  on  potash  pipette,  being  careful  to 
displace  with  water  all  air  that  may  be  in  connections.  Open  C 
to  A,  lower  L  and  draw  in  loo  cc.  of  gas.  Close  C,  raise  L, 
open  C  to  D,  and  allow  gas  to  flow  into  M  until  the  water  level 
is  at  O,  and  close  Z.  Take  the  reading  on  burette  after  allowing 
a  minute  for  water  to  run  down  off  the  sides  of  the  burette,  add 
I  cc.  to  observed  reading  for  the  i  cc.  gas  occupying  space  be- 
tween O  and  cock  C.  Disconnect  from  sample  tube  or  gas  supply 
as  the  case  may  be.  Open  C  to  B,  raise  L  and  allow  gas  to  flow 
into  K,  until  the  water  from  burette  reaches  the  bulbed  portion 
of  K,  being  careful  to  draw  the  i  cc.  from  manometer  and  to 
force  that  into  the  potash  likewise.  Turn  C  to  D  and  adjust 
water  level  at  N  in  M.  Turn  C  to  B,  lower  L,  and  draw  back 
gas  until  the  potash  solution  just  reaches  its  previous  position 
above  C  and  close  C.  Raise  L  and  turn  C  quickly  through  arc 
of  i8o.°  so  as  to  allow  no  gas  to  flow  back  to  B  while  turning 
cock  so  that  the  interior  of  the  burette  communicates  with  man- 
ometer A^.  Raise  L  until  water  in  M  is  level  with  O,  close  Z 
and  read  burette,  adding  i  cc.  to  observed  reading  as  before. 
The  difference  between  this  reading  and  the  preceding  gives 
directly  the  percentage  of  CO2  in  the  gas. 

Connect  absorption  pipette  containing  bromine  to  A,  resting  it 
on  stand  S,  being  careful  as  before  to  exclude  all  air  from  con- 
nections. Open  C  to  A,  raise  L,  and  force  gas  from  the  burette 
into  the  pipette  until  water  reaches  the  bulbed  portion  of  the 
pipette,  drawing  the  gas  from  the  manometer  tube  as  before, 
and  close  C.  Shake  the  bromine  pipette  slightly  until  gas  is  col- 
ored by  bromine  fumes,  open  C,  lower  L,  and  draw  gas  back  into 
burette.  Close  C,  raise  L,  open  C  to  B,  and  force  all  gas  im- 
mediately into  potash.  Close  C.  to  B,  and  open  to  D,  and  adjust 
water  level.  Open  C  to  B,  lower  L,  and  draw  back  gas  until 
potash  assumes  former  position. 

Close  C,  raise  L,  adjust  water  level  and  read  as  before,  the 
difference  between  this  reading  and  the  preceding  gives  the  per- 


ENGlNEmaNG    CHEMISTRY 


66i 


centage   of   C^Hg,,.     Disconnect   the   bromine   pipette   from    A 
and  connect  the  phosphorous  pipette. 

Force  the  gas  over  the  phosphorus  as  was  done  with  the  bro- 
mine pipette,  turn  C  to  D,  raise  L  and  adjust  water  level;  close 
C.     If  no  white  fumes  are  given  off  by  the  gas  when  in  the 


Fig,  130. 


pipette  it  is  a  sure  indication  that  all  of  the  C„H2„,  compounds 
in  the  gas  have  not  been  completely  removed.  In  this  event  it 
is  necessary  to  again  pass  the  gas  into  the  bromine  pipette.  If 
fumes  are  given  off  wait  a  minute  or  two  to  allow  them  to  par- 
tially condense,  then  open  C  to  A,  lower  L,  and  draw  gas  back 
into  burette.     Close  C,  raise  L,  open  C  to  D,  adjust  water  level 


662  ENGINEERING   CHEMISTRY 

at  O,  and  take  reading.  The  difference  between  this  reading 
and  the  preceding  reading  gives  percentage  oxygen  present.  Dis- 
connect phosphorus  pipette  and  connect  double  absorption  pipette 
containing  cuprous  chloride,  being  careful  to  have  all  capillaries 
filled  with  the  solution.  Open  C  to  A,  raise  L  and  force  all  gas 
over  one  solution  of  cuprous  chloride.  Shade  for  two  or  three 
minutes  and  then  draw  gas  back  into  burette  until  solution  just 
passes  cock  on  cuprous  chloride  pipette;  turn  this  cock  so  as  to 
connect  with  other  solution  of  cuprous  chloride,  raise  L  and 
force  gas  over  second  solution  to  remove  last  of  carbon  mon- 
oxide, and  close  C.  Shake  for  a  few  minutes,  draw  gas  back  into 
burette,  and  then  immediately  force  it  into  the  potash  pipette. 
Adjust  water  level,  draw  gas  back  from  potash  pipette  and  take 
reading.  The  difference  between  this  reading  and  the  preceding 
gives  percentage  of  carbon  monoxide. 

It  is  important  to  notice  that  even  with  the  precaution  of  us- 
ing two  pipettes  with  freshly  prepared  cuprous  chloride  the  ab- 
sorption of  the  carbonic  oxide  is  seldom  complete,  usually  a  trace 
remaining  unabsorbed.  However,  this  fact  introduces  no  error 
in  the  analysis,  as  this  residue  of  carbonic  oxide  can  be  deter- 
mined by  the  combustion  made  to  determine  hydrogen. 

The  residue  of  the  gas  mixture  remaining  after  the  absorption 
may  consist  of  the  following : 

H^  +  CO  -f  N,  -f  CH,  +  C^H^,  C3H3,  etc. 

For  all  ordinary  purposes  it  is  sufficient  to  assume  that  the 
highest  parraffin  present  is  CgHe,  as  all  others  higher  than  this 
exist  only  in  traces. 

There  being  no  satisfactory  known  absorbent  for  any  of  these 
gases,  recourse  is  had  to  the  method  of  combustion. 

The  analysis  is  accordingly  continued  as  follows : 

The  double  absorption  pipette  is  replaced  by  the  storage  pipette 
containing  gas  saturated  water.  Pass  approximately  15  cc.  of 
the  residue  back  into  the  potash  by  opening  Z,  raising  L  and  open- 
ing C  to  B.  Turn  C  to  A  and  pass  remainder  of  residue  into 
storage  pipette.  Close  pipette  with  a  pinch  cock  and  disconnect. 
Adjust  water  level  in  M  at  A^.     Turn  C  to  A  and  by  lowering  L, 


I 


ENGINEERING   CHEMISTRY  663 

draw  into  the  burette  about  85  cc.  of  air.  Close  C,  raise  L  and 
open  C  to  D,  draw  the  gas  stored  over  the  potash  into  the  bur- 
ette, close  C,  raise  L,  turn  C  quickly  through  arc  of  180°  to  con- 
nect with  D,  adjust  water  level  at  O,  close  Z  and  take  reading. 
The  increase  over  the  previous  reading  is  the  amount  of  gas 
taken  for  the  explosion. 

Connect  mercury  explosion  pipette  at  A  and  pass  mixture  of 
gas  and  air  into  pipette  and  explode,  first  partly  withdrawing 
glass  connecting  tube  from  rubber  connection  and  placing  clip 
on  same.  Adjust  water  level  in  M  at  A^,  draw  back  gas  from  ex- 
plosive pipette  and  measure  contraction  resulting  from  the  ex- 
plosion. Pass  the  gas  into  potash,  and  the  resulting  contraction 
gives  the  amount  of  carbonic  acid  formed  during  the  explosion. 
Disconnect  explosion  pipette  and  connect  phosphorus  pipette. 
Pass  gas  residue  over  phosphorus  to  remove  all  oxygen  in  excess 
of  that  which  was  required  for  explosion  and  measure  the  amount 
of  nitrogen  left.  This  gives  nitrogen  introduced  with  gas.  By 
subtracting  amount  of  air  used  for  explosion  by  79.2  from  this 
reading,  one  obtains  nitrogen  introduced  with  gas  for  explosion. 
This  multiplied  by  factor  obtained  by  dividing  the  amount  of  gas 
residue  taken  for  the  explosion  into  the  whole  amount  of  gas 
left  after  absorbing  carbon  monoxide,  gives  the  total  nitrogen 
in  the  original  sample  of  gas  taken  for  analysis.  The  percentage 
of  nitrogen  thus  obtained  should  check  that  obtained  by  subtract- 
ing the  sum  of  the  other  constituents  in  the  gas  from  100. 
The  equations  obtained  from  the  explosion  are  as  follows : 
(i)   Contraction  in  volume  =  3/2U0  +   >^CO   +  2CH^  + 

2/2C,He. 

(2)  CO,  formed  =  CO  -f  CH,  +  2C,¥[,. 

(3)  Residual  nitrogen  =  Ng  +  N^, 

where  N^  is  the  nitrogen  introduced  with  the  air. 

An  examination  shows  that  the  equations  i  and  2  contain  4 
unknown  quantities  and  therefore  two  more  equations  are  needed 
for  the  solution.  Fortunately,  the  method  of  fractional  combus- 
tion over  palladium  affords  the  needed  information.  As  is  well 
known,  when  a  mixture  of  hydrogen  and  CH.^  with  oxygen  or 


664  KNGINEKRING   CHEMISTRY 

air  is  passed  over  heated  palladium  black,  the  hydrogen  burns 
to  H.O,  but  the  CH^  remains  unaltered.  If  CO  and  any  of  the 
higher  parraffins  are  also  present,  the  CO  burns,  but  the  parraffins 
do  not. 

Returning  to  the  analysis,  proceed  as  follows :  Fill  burrette  to 
A  by  raising  L,  adjust  water  level  at  A^  and  M.  Draw  m  about 
70  cc.  air  and  measure  it.  Connect  storage  pipette  and  draw  in 
about  30  cc.  gas  residue,  and  measure,  the  increase  in  volume 
giving  the  amount  of  gas  taken  for  combustion. 

Place  explosion  pipette  with  mercury  level  about  one-half  up 
to  capillary,  on  stand  S,  connect  combustion  tube  to  A  and  ex- 
plosion pipette,  equalize  pressure  in  combustion  tube  and  gas 
burette  and  remeasure  gas  in  burette.  Place  combustion  tube  in 
hot  water  by  resting  beaker  containing  water  on  T  and  pass  gas 
mixture  backward  and  forward  over  palladium  until  there  is  no 
future  contraction,  measure  gas  and  decrease  in  volume  gives 
contraction  due  to  combustion  of  hydrogen  and  carbon  monox- 
ide.   The  equations  are : 

(4)  Contraction  in  volume  ^=  3/2H0  +  ^CO. 

(5)  CO2  former  =  CO. 

From  these  two  equations,  the  value  of  hydrogen  and  CO  may 
be  readily  determined. 

For  the  sake  of  simplicity,  let  us  now  assume  that  the  quan- 
tity of  gas  residue  was  used  in  both  the  explosion  and  the  com- 
bustion. 

We  may  then  subtract  equation  (4)  from  (i)  and  (5)  from 
(2),  whence,  designation  the  difference  between  the  contraction 
due  to  combustion  by  the  letter  (a)  and  the  difference  in  the  CO2 
formed  by  the  letter  ( ^ )  we  find 

(6)  2CH, -f  2>^  C,H,  =  «. 

(7)  CH, +  2C,H,         =b. 

Ab  —  2a 


whence  (8)  C^H, 
and  (9)    CH. 


3 

4^  —  5b 
3 


ENGINEEJRING   CHEMISTRY  665 

A  very  useful  check  on  the  accuracy  of  this  determination  is 
obtained  from  the  following: 

Volume  of  gas  taken  for  explosion 
=  H2  +  N.  +  CO  +  CH4  +  C.He.  H2  +  CO  are  found  by 
(4)  and  (5),  and  A^  is  given  by  (3).    Therefore,  we  have 

(10)  Volume  taken  =  (H^  +  N2,  +  CO)  =  CH^  +  CoHg  and 
this  value  should  be  the  same  as  the  algebraic  sum  of 

(8)  and  (9)  or 

(11)  Volume  taken  +  (H,  +  N,  +  CO)  =  ^^izl' 

This  method  if  carefully  pursued  will  give  results  that  are  ex- 
tremely accurate,  and  what  is  much  to  be  desired,  the  method  is 
very  rapid.  Analyses  have  repeatedly  been  made  in  from  30  to 
35  minutes. 

JUNKER'S  GAS  CALORIMETER. 

The  sectional  drawing  (Fig.  131)  shows  the  instrument  to  con- 
sist of  a  combustion  chamber  surrounded  by  a  water  jacket,  the 
latter  filled  with  a  great  many  tubes.  To  prevent  loss  by  radia- 
tion the  water  jacket  is  surrounded  by  a  closed  air  space.  The 
whole  apparatus  is  constructed  of  copper  as  thin  as  is  compatible 
with  strength.  The  water  enters  the  water  jacket  at  the  bottom, 
and  leaves  it  at  the  top,  while  the  hot  combustion  gases  of  the 
flame  of  the  gas  that  is  on  trial  enter  the  tubes  at  the  top  and 
leave  them  at  the  bottom.  There  is,  therefore,  not  only  a  very 
large  surface  of  thin  copper  between  the  gases  and  the  water, 
but  the  two  move  in  opposite  directions,  during  which  process  all 
the  heat  generated  by  the  flame  is  transferred  to  the  water,  and 
the  waste  gases  leave  the  apparatus  approximately  at  atmos- 
pheric temperature.  The  gas  to  be  burned  is  first  passed  through 
a  meter,  and  then  to  insure  constant  pressure,  through  a  pressure 
regulator.  The  source  of  heat  in  relation  to  the  unit  of  time  is 
thus  rendered  stationary,  and,  in  order  to  make  the  absorbing 
quantity  of  heat  also  stationary,  two  overflows  are  provided  at 
the  calorimeter,  making  the  head  of  the  water  and  the  rate  of 
flow  of  the  same  constant.  The  temperatures  of  the  water  enter- 
ing and  leaving  the  apparatus  can  be  read  at  the  respective  ther- 


666 


e;ngine:e:ring  chemistry 


mometers;  as  shown  before,  the  quantities  of  heat  and  water 
passed  through  the  apparatus  are  constant.  As  soon  as  the  flame 
is  Hghted  the  temperature  of  the  exit  thermometer  will  rise  to  a 
certain  point  and  will  nearly  remain  there.  All  data  for  ascer- 
taining the  heat  given  out  by  the  flame  are  therefore  available. 


Fig.  13 


Cold  water  inlet. 

Strainer. 

Overflow  to  calorimeter. 

Upper  container. 

Waste  overflow. 

and  7.  Fall  pipe  and  joint. 

Drain  cock. 

Adjustment  cock. 

Cold  water  thermometer. 

Air  jacket. 

Perforated  spreading  ring. 

and  16.  Water  jacket. 

Baffle  plates  with  cross  slots. 

Lower  overflow. 

Lower  container. 

Hot  water  overflow. 

Heated  water  outlet. 

Gas  nipple. 

Air  supply  regulator. 

Gas  nozzle. 

Clamp  for  burner. 

Burner  holder. 

Burning  cap. 

Combustion  chamber. 

Roof  of  combustion  chamber. 

Cooling  tubes. 

Receiver  for  combustion  gases. 

Outlet  for  combustion  gases. 

Throttle  for  combustion  gases. 

Brass  base  ring. 

Condensed  water  outlet. 

37  and  38.  Air  jacket. 

Test  hole  in  air  jacket. 

Hot  water  thermometer. 


All  that    is  required  is  to  measure  simultaneously  the  quantity 
of  gas  burned  and  the  quantity  of  water  passed,  and  the  differ- 


KNGINKERING   CH£;MISTRY 


667 


ence   in   temperature   between  the   entering   and   leaving   water. 
Centigrade  thermometers  and  2-liter  flasks  are  required. 

The  meter  shows  o.i  of  a  cubic  foot  per  revolution  of  the  large 
hand,  the  circumference  being  divided  into  100  parts,  so  that 
0.00 1  can  be  read  accurately.  The  water  supply  is  so  regulated 
that  the  overflow  is  working  freely,  and  the  water-admission  cock 


Fig.  132. 

is  set  to  allow  2  liters  of  water  to  pass  in  about  a  minute  and  a 
half.  The  calorimeter  is  now  ready  to  take  the  reading.  The 
cold  water,  as  a  rule,  has  a  sufficiently  constant  temperature  that 
we  note  it  only  once:  it  is  now  17.2°  C.  As  soon  as  the  large 
index  of  the  meter  passes  zero,  note  the  state  of  the  meter  and 
at  the  same  time  transfer  the  hot-water  tube  from  the  funnel  into 
the  measure  glass,  and  while  that  is  being  filled  note  the  tempera- 
ture of  the  hot  water  at  say  10  intervals,  to  draw  the  average. 


668  ENGINEERING   CHEMISTRY 

The  temperatures  are  43.8°,  43.5°,  43-5°,  44-2°,  44.1°,  43-9°, 
43.8°,  43.7°,  43.8°,  and  43.7°,  making  the  average  43.8°. 

The  measure  glass  is  now  filled ;  turn  the  gas  out.  Find  from 
the  readings  of  the  meter  at  the  beginning  and  the  end  of  the 
experiment  that  there  was  burned  0.35  cubic  foot,  by  means  of 
which  the  temperature  of  the  2  liters  of  water  was  raised  26.6° 
C. ;  viz.,  43.8°  —  17.2°  =  26.6°  C.    The  calculation  is  as  follows : 

WT 

where  H  =1  the  calorific  value  of  i  cubic  foot  of  gas  in  calories, 
W  =^  the  quantity  in  liters  of  the  water  heated,  T  =  the  differ- 
ence in  temperature  between  the  two  thermometers  in  degrees 
C,  and  G  ^=  the    quantity    in  cubic    feet    of    gas    used,    then 

^         2  X  26.6  ,     . 

H  =  ^152  calories 

per  cubic  foot  or  604  (152  X  3-968)  B.  t.  u.  per  cubic  foot. 

It  is  mentioned  before  that  the  effect  of  the  cooling  water  is 
such  that  the  waste  gases  leave  the  calorimeter  at  about  atmjos- 
pheric  pressure.  All  hydrocarbons  when  burned  form  a  con- 
siderable quantity  of  water,  which  in  all  industrial  processes  es- 
capes with  the  waste  gases  as  steam.  The  latent  heat  of  this 
steam  is  therefore  not  utilized  when  firing  a  stove  or  driving  an 
engine  with  gas;  in  the  above  result,  however,  the  latent  heat  is 
included,  because  in  the  copper  tubes  the  steam  is  condensed, 
and  its  heat  is  transferred  to  the  circulating  water  and  measured 
with  the  rest.  The  condensed  water  runs  down  the  tubes  which 
are  cut  off  obliquely  to  allow  the  drops  to  fall  off  easily,  and  is 
collected  in  the  lower  part  of  the  apparatus  from  where  it  runs 
through  the  little  tube  into  a  measure  glass.  In  condensing, 
steam  gives  off  0.6  calorie  for  every  cubic  centimeter  of  water 
formed.  If  therefore  a  graduated  (cc.)  cylinder  be  placed  under 
the  little  tube  the  amount  of  water  generated  by  burning,  say  i 
cubic  foot  of  gas,  can  be  directly  measured. 

From  burning  i  cubic  foot  of  gas,  we  have  collected  27.25 
cc.  of  condensed  water,  and  must  therefore  deduct  16.35  calories 
from  the  gross  value  found  above,  which  gives  the  net  calorific 


i:nginee:ring  chemistry 


669 


value  of  the  gas  tested  as  135.65  calories  or  538  B.  t.  u.  per  cubic 
foot. 

The  calorimeter  is  placed  so  that  one  operator  can  simultane- 
ously observe  the  two  thermometers  of  the  entering  and  escaping 
water,  the  index  of  the  gas-meter,  and  the  measuring  glasses.  No 
draft  of  air  must  be  permitted  to  strike  the  exhaust  of  the  spent 
gas. 

The  water  supply  tube  is  connected  to  the  nipple  in  the  center 
of  the  upper  container ;  the  other  nipple  is  provided  with  a  waste 
tube  to  carry  away  the  overflow.  This  overflow  must  be  kept 
running  while  the  readings  are  being  taken. 

The  nipple  through  which  the  heated  water  leaves  the  calo- 
rimeter, is  connected  by  an  india-rubber  pipe  with  the  large  meas- 
ure glass,  and  the  water  must  be  there  collected  without  splash- 
ing. The  smaller  measure  glass  is  placed  under  the  tube  to  col- 
lect any  condensed  water. 

Table  of  Resume  of  Tests  upon  London  Coal  Gas. 


B 
0 

V 

3 

0 

'2 

6ri 

a.2 

i 

S 

'    £ 

•0 

'0 

2 

""b 

0^ 

0 

u 

(LI 

V 

V 

3 

11  3 

^0 

0 

3 

e 

3 

3 

2^- 

^ 

^  2 

fa 

J3 

tr. 

s 

K^ 
s  = 

S^ 

8 
0; 

0 

V 

ti— 

V  0 

S-o 

0  ^ 

K 

0 

H 

H 

J^ 

« 

0 

H 

u 

0 

hT 

% 

First  Day 

21.0 

15.322 

26.113 

10.79 

0.0407 

.... 

25.7 

165.3 

15-4 

149.9 

Second  Day  

22.5 

12.9  - 

27.68 

14.78 

0.0584 



27.4 

165.9 

16.4 

148.5 

Third  Day 

17.5 

13-71 

28.6 

14.89 

0.1 103 

17.5 

26.43 

164.8 

15.86 

148.94 

Fourth  Day 

17-5 

13.75 

28.53 

i4.7« 

0.1 103 

17.4 

26.43 

165.6 

i5.«6 

149.74 

After  the  thermometers  have  been  placed  in  position  with 
their  india-rubber  plugs,  the  water  supply  is  turned  on  by  the 
cock,  and  the  calorimeter  filled  with  water  until  it  begins  to  dis- 
charge. No  water  must  at  this  period  exude  from  the  smaller 
pipe  or  from  the  test  hole  under  the  air  jacket,  otherwise  this 
would  prove  the  calorimeter  to  be  leaking. 

Experiments  made  with  this  calorimeter  at  the  Stevens  Insti- 
tute are  recorded  in  the  Stevens  Indicator,  October,  1896. 


6/0  KNGINKKRING    CHEMISTRY 

The  gas  used  was  carbureted  water  gas,  'Xowe  Process," 
composed  as  follows : 

Per  cent,  by  volume 
CO2 -2.20 

lUuminants  <  Q^H^  V   12  80 

iCeHj 

O 0.00 

CO 24.20 

CH, 17.83 

H 37-95 

N 5.02 

100.00 

The  theoretical  heating  value  of  this  gas  is  662  B.  t.  u.  per 
cubic  foot.  The  heating  value  as  determined  with  the  Junker 
calorimeter  is  668  B.  t.  u.  per  cubic  foot. 


MANUFACTURE  OF  WATER  GAS. 

The  water  gas  system  consists  in  the  decomposition  of  steam  at 
a  high  temperature  by  incandescent  carbon,  thereby  producing 
hydrogen  and  carbon  dioxide:  2H204-C:=2H2+C02.^ 

In  an  excess  of  carbon,  the  carbon  dioxide  saturates  itself  with 
another  carbon  atom,  forming  carbon  monoxide  C02+C=2CO, 
making  the  finished  product  2H2  +  2CO. 

In  practical  working  the  reduction  of  carbon  dioxide  to  mon- 
oxide is  never  quite  perfect,  the  unpurified  gas  usually  contain- 
ing about  3  per  cent,  of  carbon  dioxide,  to  be  extracted  (as  in 
coal  gas)  by  lime  purification. 

As  the  gas  in  the  process  of  manufacture,  passes  from  the  gen- 
erator to  the  carbureters  it  is  enriched  by  means  of  crude  oil  or 
cheaper  distillates :  hence  the  name  carbureted  zvater  gas. 

The  generator,  carbureter,  and  superheater  are  cylindrical 
steel  shells,  thickly  lined  with  special  fire-bricks,  between  which 
and  the  metal  are  annular  spaces  packed  with  non-conducting 
material.  The  generator  is  usually  supported  on  short  columns, 
as  illustrated,  leaving  cartage  room  under  the  hopper-shaped  ash- 

1  Humphrey's  and  Glasgows:  "Carbureted  Water  Gas,"  1895. 


ENGINEERING   CHEMISTRY  67I 

pit.  The  grate,  controlled  by  the  several  cleaning  doors,  is  lo- 
cated slightly  above  the  ash-pit,  and  the  fire  is  charged  with  coke 
through  the  door  in  the  extreme  top. 

The  generator  is  connected,  both  above  and  below  the  fuel-bed, 
with  the  top  of  the  carbureter,  the  bottom  of  which  leads  laterally 
into  the  adjoining  superheater.  The  carbureter  and  superheater, 
often  referred  to  as  the  "fixing  chambers,"  are  filled  with  checker 
work,  affording  such  an  enormous  heating  surface  that  even  the 
heaviest  distillates  can  be  permanently  gasified  at  the  low  tem- 
perature necessary  to  the  highest  illuminating  effect.  The  en- 
riching oil  is  introduced  at  the  top  of  the  carbureter. 

The  oil  heater  is  a  simple  and  practical  arrangement  for  pre- 
heating the  oil  on  its  way  to  the  carbureter  by  means  of  the  hot 
gas  escaping  from  the  superheater. 

Operation. — A  fire  is  started  in  the  generator,  which  is  then 
deeply  charged  with  coke  and  opened  to  the  blast.  The  air  enters 
in  large  volume  below  the  grate  and  quickly  kindles  the  fuel, 
while  the  hot  products  resulting  from  the  partial  combustion  pass 
forward  through  the  carbureter  and  superheater  and,  after  part- 
ing with  their  sensible  heat,  escape  into  the  stack.  As  soon  as 
these  generator  gases  have  sufficiently  warmed  the  checker-work, 
supplies  of  secondary  air  are  admitted  to  the  top  of  the  carbu- 
reter and  the  bottom  of  the  superheater,  respectively,  and  the 
combustion  regulated  to  give  the  requisite  temperatures  in  the 
two  vessels  simultaneously.  The  generator  fire  being  in  proper 
condition,  and  the  carbureter  and  superheater  at  the  desired  tem- 
peratures, the  apparatus  is  ready  for  gas-making.  The  blasts 
are  shut  off  one  by  one,  beginning  with  that  of  the  super- 
heater; the  stack  valve  is  closed;  steam  is  admitted  under  the 
fuel  bed,  and  having  traversed  it,  passes  as  water-gas  into  the 
top  of  the  carbureter.  At  this  point  the  oil  is  introduced,  and 
encountering  the  heated  checker-work  is  vaporized  and  ultimately 
gasified  in  presence  of  the  hot  water-gas.  This  process  continues 
until  the  temperature  of  the  fire  and  the  checker-work  are  suffi- 
ciently reduced.  The  oil  is  then  shut  off;  next  the  steam;  and 
the  stack  valve  being  opened  the  blasts  are  again  admitted  and 
the  energy  of  the  fire  and  the  checker-work  recuperated  as  first 


liNGlNEKRING   CHEiMISTRY  673 

described.  The  generator  is  supplied  with  fuel  at  intervals  of 
from  forty-five  to  sixty  minutes,  and  cleaned  usually  once  during 
each  shift.  The  gas  passes  from  the  seal  through  the  scrubbers 
and  condensers  and  is  subsequently  deprived  of  its  carbon  dioxide 
and  treated  for  its  slight  sulphur  impurities  in  the  manner  com- 
mon to  coal  gas. 

Uncarbureted  water  gas  has  the  following  composition:^ 

Pet  cent. 

H 4932 

CH4   7.65 

CO 37.97 

CO2    0.14 

N    4-79 

O    0.13 

Total   100.00 

and  after  carbureting 

Per  cent. 

H    38.05 

CH4   11.85 

CO 29.40 

O  o.io 

CO2    ". o.io 

N    3.71 

Illuminants    16.79 

Total 100.00 

The  heating  power  of  the  uncarbureted  gas  per   cubic   foot 
would  be : 

Products  condensed 
B.  t.  u. 

H    0.4932  X     348.0    =  171.63 

CH4      0.0765    X    1,065.0      =:      81.47 

CO  0.3797  X    34956  =  132.72 

Total   385.82 

and  the  heating  power  of  the  carburetted  water  gas  per  cubic 
foot  would  be : 

1  King's  Treatise  on  Coal  Gas,"  Vol.  Ill,  p.  362. 

43 


674  ENGINEERING   CHEMISTRY 


Products  condensed 
B.  t.  u. 


H    0.3805  X     348.0    =  122.41 

CHi    O.I  185  X  1,065.0    =  126.20 

CO    0.2940  X     349- 56  =  102.77 

CO2 

O    

N 

Illuminants    0.1679  X  2,000.0     =  335.80 


Total 697.18 

An  analysis  of  a  sample  of  London  (Eng.)  coal  gas  gives  the 
following : 

Per  cent. 

H    27.70 

CH4    50.00 

CO    6.80 

C2H4    13.00 

N    0.40 

O  

CO2     O.IO 

Aqueous  vapor   2.00 


Total   : 100.00 

The  heating  power  will  be,  per  cubic  foot, 


Products  condensed 
B.  t.  u. 


H   0.2770  X  348.0    =    96.39 

CH4   0.5000  X  1,065.0    =  532.50 

CO    0.0680  X  34956  =    23.77 

C2H4   0.T300  X  1,6730    =  217.49 


Total   870.15 

and  when  the  products  of  combustion  are  in  a  state  of  vapor  (for 
instance  328°  F.)   the  heating  power    per    cubic    foot    will    be 

B.  t.  u. 

H   0.2770  X  264  =    73.12 

CH4   0.5000  X  853  —  426.50 

CO    0.0680  X  315  =    21.42 

C2H4   0.1300  X  1,400  =  182.00 


Total   703.04 


ENGINEEJRING   CHEMISTRY 


675 


There  are  few  complete  analyses  of  purified  coal  gas  known,^ 
i.  e.,  Heidelberg  gas  by  R.  Bunsen,  Konigsburg  gas  by  Bloch- 
mann,  and  Hannover  gas  by  Dr.  Fischer. 


Constituents 

Heidelberg 
gas 

Konigsberg 
gas 

Hannover  gas 

Hannover  gas 
II 

CeHe 

1.33 

0.66 

0.69 

0.59 

CaHe 

1. 21 

0.72 

0-37 

0.64 

C2H, 

2.55 

2.01 

2. II 

2.48 

CH, 

34.02 

35.28 

37-55 

38.75 

H 

46.20 

52.75 

46.27 

47.60 

CO 

8.88 

4.00 

II. 19 

7.42 

CO2 

3.01 

1.40 

0.81 

0.48 

0 

0.65 



trace 

0.02 

N 

2.15 

3.18 

I.OI 

2.02 

Total 

100.00 

100.00 

100.00 

100.00 

In  the  Wilkinson  process  the  water  gas  is  made  by  the  com- 
bined generator  and  retort  process.  (A  full  description  of  a  com- 
plete plant  will  be  found  in  The  American  Gas  Light  Journal,  57, 
399,  401.) 

An  analysis  of  a  sample  of  Wilkinson  water  gas,  made  by  the 
writer,^  gave  as  follows : 

Per  cent. 

H    39.50 

mu'^nal™^"'""1CsHeaverage| 6.60 

CPI4       3730 

CO  4.30 

N    8.20 

O  1.40 

Impurities   (HA  CO2,  H^S) 2.70 


100.00 


One  cubic  foot  contains  681.73  B.  t.  u.  products  condensed. 
G.   Lunge^  gives  an  analysis   of   ''Tessie  du   Motay"  gas  as 
follows : 

1  Wagner's  "Manual  of  Chemical  Technology"  (13th  Edition),  p.  39. 
"  Wood's  "Thermodynamics,  Heat  Motors,  and  Refrigerating  Machines,"  3rd.  edition, 
pp.  260-261. 

a  "Wassergasfabrikation  in  Neve  York,"  Zeitschrift  fur  angewandte  Chentie,  1894,  pp. 

137-142. 


676 


ENGINEERING    CHEMISTRY 


Per  cent. 

CO^   

Illuminants    14.3 

O    0.6 

CO  21.1 

H   28.8 

CH,   25.5 

N 3-1 

Total  100.00 

containing  754.61   B.  t.  u.  per  cubic  foot,  products  condensed. 
For  complete  details  regarding  the  manufacture  of  coal  gas 
consult  King's  Treatise  on  Coal  Gas,"  edited  by  Thomas  New- 
bigging,  London. 

Producer  Gas 


Constituents 

Siemen's  gas 

Anthracite 
producer  gas 

Soft  coal 
producer  gas 

00 

23-7 
8.0 
2.2 
4.1 

62.0 

27.0 

12.0 

1.2 

2.5 

57-3 
100.00 

27.0 
12.0 

2.5 
2.0 

56.5 

H 

CH, 

CO, 

N 

Total 

100.00 

100.00 

The  heating  power  of  the  Siemen's  producer  gas  will  be  134. i 
B.  t.  u.  per  cubic  foot,  of  the  anthracite  producer  gas  153.7  ^-  t-  ti. 
per  cubic  foot,  and  of  the  soft  coal  producer  gas  168. i  B.  t.  u. 
per  cubic  foot  (products  of  combustion  condensed). 

Experiments  made  in  Berlin,  Germany,  on  the  cost  of  power 
from  various  substances,  show  as  follows  •} 
H.   P.   DEVEI.OPED 

10  H.  p.  20  H.  P  30  H.  p. 

Cents  Cents  Cents 

Acetylene     5.85  5.62  5.54 

Lighting  gas   2.61  2.45  2.38 

Power  gas    2.90  2.19  i.<  ' 

Alcohol     4.14  3.86  3 

Petroleum    2.56  2.38 

Benzene    3.70  3.59 

Electricity    3.60  3.55 

^  Schweizerische  Bauzeitung,  January  26,  1901. 


ENGINEERING   CHEMISTRY  (i^^ 

NATURAL  GAS. 

Natural  gas  from  different  localities  has  a  somewhat  different 
composition,  as  may  be  seen  from  the  following  table  '} 

Pennsylvania       Ohio  Indiana  Kansas  Russia 

Carbon  dioxide   0.05  0.3  0.25  0.44  0.95 

Carbon   monoxide    ......  0.5  0.45  0,33  .... 

Marsh  gas  95.42  92.6  92.67  95.28  92.49 

Nitrogen    4.51  3.5  3.53  3.28  2.13 

Oxygen   trace  0.3  0.35  ...  .... 

Hydrogen    0.02  2.3  2.35  ...  .... 

Hydrogen  sulphide 0.2  0.15  ...  .... 

Olefiant  gas,  etc 0.3  0.25  0.67  4.11 

To  be  more  specific  and  local  in  reporting  the  analyses,  I  re- 
fer to  some  of  the  analyses  made  during  the  past  year  by  Prof. 
H.  P.  Cady  and  D.  F.  McFarland  at  the  University  of  Kansas. 
Analyses  of  natural  gas  have  been  made  from  the  following 
localities : 

Dexter,  Eudora,  lola,  Moline,  Fredonia,  Neodesha,  Lawrence, 
Erie,  Kansas  City,  Bartelsville  (I.  T.),  Bonner  Springs,  Par- 
sons, Arkansas  City,  Altamont,  Coffeyville,  Moran,  Caney,  Peru, 
Butler  (Ohio),  Chanute,  Humboldt,  New  Albany,  Altoona, 
Mound  City,  Buffalo,  Blackwell  (Okla.),  Garnett,  Olathe,  Paola, 
Burlington,  Augusta,  Marion  (Tnd.j,  Morgantown  (W.  Va.), 
Elmdale,  Eureka,  Sheffield  (Mo.),  and  Jennings  (La.). 

Composition  of  37  Samples  of  Natural  Gas 

Pipe-lime       Chanute    Elmdale      Olathe  Dexter  Caney         Blackwell 

O2   . . .     0.24  .10  .30  trace  .10  .10  .50 

CO2         1.94  . .  .15  00  .00  .81  .00 

C2H4       5-.  ••  -55  .10  .00  .10  .61 

CO . .  .00  .00  .00  .00  .00 

CH4   .  94.30  94.70  78.60  84.40  14.33  ,92.40  83.40 

CzHg       0.75  .00  T.1\  .00  1.06  .00  10.31 

H2 .00  .00  .00  trace  .00  .2^2i 

He..       0.17  .24  .56  .40  1.64  .08  .16 

N2    ..     2.6od  4.96  12.13d  i5.iod  82.87d  6.46d  5.i9d 

4.83r  4.96r  i6.04r  i6.i5d  6.69r  7.35r 

1  Prof.  E.  H.  S.  Bailey,  Progressive  Age,  Aug.  15,  1907. 


678  e:ngine:e:ring  chemistry 

It  will  be  seen  that  the  fuel  value  of  the  gas  diminishes  to- 
ward the  west  and  southwest;  for  example,  Dexter,  14.33;  ^l"^" 
dale,  78.60;  Blackwell,  Okla.,  8340. 

Although  there  is  considerable  difference  in  the  composition 
of  natural  gas  from  different  places  in  this  field,  yet  in  all  cases 
practically  the  only  valuable  fuel  constituent  in  the  marsh  gas. 
By  the  combustion  of  each  1,000  cubic  feet  of  this  gas,  as  prev- 
iously noticed,  2,000  cubic  feet  of  steam  would  be  found,  and 
when  this  is  condensed  to  water  we  shall  have  36  quarts  of  water, 
or  9  gallons.  This  large  quantity  of  water  causes  considerable 
inconvenience  in  the  use  of  ordinary  stoves  and  furnaces,  on  ac- 
count of  dripping  down  the  chimney  and  frequently  soaking 
through  the  brick  and  defacing  the  walls. 

For  gas  engines,  it  seems  to  be  admitted  that  the  gas  is  best 
which  contains  a  low  percentage  of  hydrogen  and  of  inert  gas. 
The  richer  the  gas,  the  less  there  is  to  be  handled  and  stored; 
the  lower  the  percentage  of  hydrogen,  the  less  will  be  the  flame 
temperature  of  the  mixture  and  the  slower  the  combustion,  which 
is  said  to  permit  of  higher  degrees  of  compression,  and  conse- 
quently greater  efficiency  in  the  engine  cylinder.  Natural  gas 
appears  to  answer  these  conditions  admirably.  Natural  gas  has 
a  calorific  value  of  about  1,000  B.  t.  u.  per  cubic  foot. 

Methane  is  the  principal  constituent  of  natural  gas.  Ethylene 
is  not  an  abundant  constituent  of  gases. 

When  we  attempt  to  use  natural  gas  in  a  furnace  with  an  air 
blast,  our  experiments  show  that  we  can  readily  get  temperature 
of  1,400°  C.  or  2,552°  F.  This  will  readily  melt  brass  or  copper. 
The  furnace  works  admirably  for  the  cupeling  of  gold  and  silver. 
In  the  ordinary  bunsen  burner  a  temperature  of  about  850°  C. 
is  attained.  The  flame  goes  out  very  readily,  because  there  is 
no  hydrocarbon  to  transmit  flame.  Bunsen  burners  with  differ- 
ent proportions  from  those  ordinarily  used  must  be  constructed 
for  use  with  natural  gas.  They  must  have  a  large  tube  and  a 
longer  one  for  the  mixing  of  gas  and  air,  as  so  much  air  is 
required  for  complete  combustion. 

The   foregoing   statements   have    reference   to   the   theoretical 


EJNGINKERING   CHE:mISTRY  679 

amount  of  heat  that  can  be  produced  by  the  combustion  of  the 
fuels.     So  theoretically: 

One  ton  of  oil  produces  40,ocx),cx)0  B.  t.  u. 

One  ton  of  bituminous  coal  produces  25,000,000  B.  t.  u. 

One  ton  of  anthracite  coal  produces  26,000,000  B.  t.  u. 

One  thousand  cubic  feet  natural  gas  produces  1,000,000  B.  t.  u. 

But  combustion  is  incomplete  and  there  is  always  an  increased 
loss  in  burning  some  parts  of  the  fuel.  We  must  heat  and  carry 
off  four  parts  of  nitrogen  for  every  part  of  oxygen  that  we  use.' 
The  water,  also,  is  changed  to  steam  and  carries  off  large  quan- 
tities of  heat. 

From  some  experiments  made  in  the  university  laboratory 
some  time  ago,  it  was  found  that  one  ton  of  soft  coal  was  equiv- 
alent in  water  evaporation  power  to  about  20,000  cubic  feet  of 
gas. 


ACETYLENE.! 

Manufacture. — 7\cetylene  is  produced  from  calcium  carbide  by 
the  action  of  water  on  the  latter,  the  formula  for  this  reaction 
being  CaC^  +  2H0O  =  C2H2  -f  Ca  (OH)2.  Sixty- four  parts  by 
weight  of  calcium  carbide  and  36  parts  by  weight  of  water 
give  26  parts  by  weight  of  acetylene  and  this  formula  is  very 
closely  borne  out  by  practice  in  the  best  forms  of  generators  and 
with  a  good  quality  of  carbide.  The  action  is  attended  by  the 
evolution  of  great  heat,  the  liberation  of  gas  being  instantaneous 
on  the  application  of  water,  and  the  residue  of  this  action  being 
slaked  lime. 

The  preparation  of  this  gas  is  accomplished  in  generators, 
which  may  be  sub-divided  into  two  classes,  namely, 

(i).  Water  feed, 

(2).  Carbide  feed. 

At  the  inception  of  the  acetylene  industry,  the  first  class  of 
generator  was  veiy  often  employed  and  contained  a  chamber  in 
which  were  trays  containing  the  carbide  in  lumps,  and  superim- 

1  Written  and  communicated  to  the  Editor  by  R.  E  Briickner,  M.  E.  of  New  York. 
He  graduated  from  Stevens  Institute  ot  Technology  in  iS86,  and  is  considered  a  standard 
authority  upon  acetylene. 


68o  e;nginee:ring  chemistry 

posed  tipon  it,  perforated  pipes  or  other  devices  for  the  admission 
of  water  to  the  carbide,  The  regulation  of  the  supply  of  water 
was  governed  by  the  pressure  within  the  generator  chamber  pro- 
duced by  the  gas  generated. 

This  type  of  generator  has  the  following  defects,  which  were 
very  soon  recognized  and  this  particular  type  is  now  practically 
obsolete.  Its  first  fault  was  what  is  known  as  "dry  generation," 
or  generation  of  gas  with  insufficient  water.  This  produces, 
primarily,  hot  gas  and,  because  of  the  insufficient  water  supply,  it 
has  no  chance  to  give  up  any  impurities  which,  in  a  correctly 
designed  machine,  may  be  given  off  to  the  water.  Gas  produced 
by  this  process  contains  all  of  the  phosphureted  and  sulphureted 
hydrogen,  together  with  the  ammonia,  of  the  carbide.  The 
presence  of  air  in  these  generators  would  be  a  distinct  menace 
for,  whereas  the  temperature  of  dissociation  of  pure  acetylene 
at  atmospheric  pressure  is  1,436°  F.,  this  temperature  is  materially 
reduced  by  pressure  and  by  mixture  with  the  gas  of  a  per- 
centage of  air.  These  troubles  soon  led  to  the  abandoning  of 
this  type  of  generator. 

Carbide  Feed  Generators. — At  the  present  time,  the  generators 
in  common  use  are  fitted  with  a  hopper  in  which  the  lump  carbide 
is  stored  and  from  which  it  is  automatically  fed  into  a  chute  en- 
tering the  generator  chamber.  (Fig.  134).  This  chamber  is  filled 
with  water  and,  by  the  rules  of  the  National  Board  of  Fire 
Underwriters,  must  contain  one  gallon  of  water  for  every  pound 
of  hopper  capacity  in  carbide.  The  evolution  of  gas  and  its  use 
from  the  generator  automatically  operates  the  feeding  mechanism, 
so  that  only  the  necessary  amount  of  carbide  is  fed  into  the  gen- 
erator to  supply  the  demands  thrown  upon  it. 

For  central  station  work,  two  methods  are  pursued.  One 
is  to  use  a  generator  with  water  motor  attached  to  its  feeding 
mechanism;  the  other,  to  feed  by  hand  as  the  presence  of  a  man 
is  always  necessary  in  a  plant  of  any  capacity.  (Fig.  135.)  The 
generator  itself  is  fitted  with  grids  located  about  a  foot  from 
the  bottom  of  the  chamber  and  upon  these  grids  the  carbide  falls 
and  is  surrounded  by  water.  This  permits  it  to  give  up  every 
particle  of  its  gas  and  decompose  completely  instead   of  being 


DNGINEJERING   CHEJMISTRY 


68 1 


Fig.  134.— General  acetylene  generator  (not  automatic).  Descriptive  references. — 
A,  hand  hole  through  which  hopper  is  filled  with  carbide.  B,  hand  hole  for  cleaning  feed 
drum.  C,  hand  hole  giving  access  to  generating  chamber.  £>,  Carbide  hopper.  £,  rachet 
wheel  operating  feed  drum.  J^,  gas  main  from  generator.  G,  gate  valve.  H,  overflow 
pipe.  /,  vent  pipe.  /,  water  supply  pipe.  A',  blow  off  pipe.  L,  blow  off  seal.  M,  blow 
off  seal  overflow.  N,  drain  pipe.  O,  drain  valve.  P,  carbide  deflector.  Q,  flange  joint 
connecting  hopper  with  generating  chamber. 


682'  e:ngine:e:ring  chemistry 

allowed  to  fall  into  the  sludge  and  eventually  pass  out  of  the 
generator  with  the  water  before  its  complete  decomposition. 
Actual  results  on  long  runs  in  plants  in  this  country  show  that  the 
carbide  delivered  from  the  Union  Carbide  Company's  Niagara 
Falls  Works  averages  4^/2  cubic  feet  per  pound  of  carbide.  This, 
of  course,  presupposes  the  use  of  a  correctly  designed  generator. 


Fig.  135. — The  general  acetylene  generator  (automatic)  for  use  of  town, 
shop  and  residence  lighting. 

Purification. — Gas  generated  from  the  best  carbide  and  in  the 
best  generators  carries  with  it  certain  impurities  which  nothing 
but  a  chemical  cleaning  will  remove.  The  effects  of  these  im- 
purities in  the  gas  are  apparent  in  that  they  form  a  certain  haze 
over  the  flame  or  produce  tails  or  fringe  on  the  top  of  the  flame. 
If  glassware  be  superimposed  above  the  flame,  a  deposit  of  these 
impurities  accumulates  on  the  glassware. 

The  most  objectionable  of  these  impurities  are  phosphorated 
and  sulphureted  hydrogen.  The  quantities  of  these  impurities 
vary  with  the  gas  produced  from  different  carbides,  but  even 
in  minute  quantities,  amounting  to  less  than   i   per  cent.,   both 


EJNGINERRING    CHE:mISTRY  683 

sulphureted  and  phosphoreted  hydrogen  affect  the  operation  of 
burners,  causing  their  stoppage  and  causing  a  deposit  upon  glass- 
ware. To  eliminate  these  impurities,  various  reagents  have  been 
tried,  the  ones  most  generally  known  being  puratylene,  heratol, 
and  Frankolin.  These,  we  may  say,  have  been  arrived  at  by  a 
process  of  elimination. 

Puratylene. — Puratylene  is  a  method  of  using  safely  chloride 
of  lime  and  consists  of  mixing  chloride  of  lime,  slaked  lime,  and 
calcium  chloride  into  a  thick  paste  and  then  dr}dng  it  at  a  tem- 
perature which  suffices  to  drive  off  a  part  of  the  water  of  crys- 
tallization without  disturbing  the  chloride  of  lime.  In  this  man- 
ner a  very  porous  mass  is  produced  of  a  certain  degree  of  hard- 
ness. The  lime  is  supposed  to  attack  the  sulphureted  hydrogen 
and  also  to  retain  any  free  chlorine,  whereas  the  chloride  of  cal- 
cium absorbs  any  ammonia  which  may  be  present. 

The  principal  objection  to  this  material  is  that  it  is  likely  to 
give  up  free  chloride.  It  is  not  a  very  good  purifier  and  acts 
upon  the  acetylene  itself.  Aside  from  this  fact,  the  chlorine 
products  are  not  sufficiently  removed  by  the  lime.  The  results 
of  qualitative  analyses  are  given  on  page  257  of  Caro,  Ludwig 
&  Vogel's  Handbuch  for  Acetylen. 

Heratol. —  Due  to  the  experiments  of  Ullmann,  the  use  of 
chromic  acid  as  a  purifier,  or  oxidizing  agent,  for  acetylene  be- 
came known.  Under  the  name  of  Heratol,  a  substance  is  pre- 
pared which  consists  of  making  a  solution  of  ten  pounds  of  water, 
three  of  chromic  acid  and  one  of  sulphuric  acid  and  saturating 
nine  pounds  of  infusorial  earth  with  this  solution,  producing  a 
reddish  mealy  mass,  very  much  resembling  corn  meal.  This 
material  is  not  sufficiently  acid  to  attack  metal  and  can,  there- 
fore, be  held  in  ordinary  galvanized  metal  boxes.  The  gas  is 
permitted  to  pass  through  these  either  from  the  bottom  to  the  top 
or  from  the  top  to  the  bottom,  and,  in  passing  through  the  mass, 
is  broken  up  into  minute  streams  by  the  finely  divided  mass. 

The  sulphureted  and  phosphoreted  hydrogen  are  completely 
removed  from  the  gas  by  this  process,  provided  the  gas  is  not 
passed  through  the  mass  at  too  rapid  a  rate  of  flow.     Under  the 


684  ENGINKEJRING    CHEMISTRY 

proper  condition  of  flow,  one  pound  of  this  mass  purifies  per- 
fectly 200  cubic  feet  of  gas. 

Frankolin. — The  use  of  this  material  is  due  to  the  researches 
of  Dr.  A.  Frank,  after  whom  it  is  named.  It  consists  in  sat- 
urating a  mass  of  infusorial  earth  with  a  solution  made  up  of 
one  part  of  cuprous  chloride,  ten  parts  of  25  per  cent,  hydro- 
chloric acid,  and  ten  parts  of  water.  The  finished  mass  is  of  a 
mealy  consistency  and  is  utilized  the  same  as  heratol,  with  the 
exception  that  it  is  too  strongly  acid  to  be  contained  in  metal 
vessels  and  must,  therefore,  be  held  in  earthenware,  clay,  cement, 
or  enameled  iron  boxes. 

This  preparation  very  readily  attacks  the  impurities  in  the 
gas  and  completely  removes  the  phosphoreted  and  sulphureted 
hydrogen  together  with  the  principal  organic  phosphorus  and 
sulphur  compounds.  In  fact  only  a  very  small  percentage  of  these 
compounds  is  not  removed  by  the  cuprous  chloride  solution. 

The  purification  is  accomplished  by  means  of  precipitation 
of  the  various  compounds  into  copper  sulphide  for  the  sulphur 
compounds,  and  into  copper  phosphide  for  the  phosphorus  com- 
pounds, or  they  remain  in  the  solution.  Its  most  important  prop- 
erty is  that  of  removing  silicon  hydride  as  effectually  as  it  does 
the  phosphorus  and  sulphur  compounds.  It  attacks  the  im- 
purities far  more  readily  than  the  other  purifying  reagents,  and, 
therefore  permits  a  more  rapid  flow  of  gas  during  purification. 

Acetylene  purified  by  this  method  may  be  tested  for  purity  by 
the  use  of  silver  nitrate.  A  piece  of  filter  paper  saturated  with  a 
5  per  cent,  solution  of  silver  nitrate,  when  held  in  the  flow  from  a 
jet,  will  not  be  discolored  by  the  gas,  whereas  the  raw  gas  im- 
mediately turns  such  paper  black. 

Drying. — Wherever  gas  is  to  be  used  for  compression  and 
storage  it  is  necessary  that  the  moisture  be  removed  from  it  be- 
fore entering  the  compressor.  This  is  accomplished  by  passing 
the  gas  through  quick,  or  unslaked,  lime,  and  then  through  cal- 
cium chloride. 

Candle-power. — Acetylene  is  commonly  known  as  a  50  candle- 
power  gas,  which  means  that  when  it  is  burned  in  the  most  ad- 
vantageous way  in  a  naked  flame,  it  delivers  50  candle-power  per 


EJNGINEERING   CHEjMISTRY  685 

foot.  This  particular  test  was  conducted  on  a  Bray  fish-tail  burn- 
er. For  commercial  purposes,  this  type  of  burner  is  not  practical 
for  acetylene.  The  gas  is  too  rich  and,  in  the  course  of  time, 
carbonizes  the  burner.  Dolan's  invention  produced  a  burner 
with  a  cupped  orifice.  Into  this  cup  air  ducts  lead.  These  air 
ducts  supply  air  around  the  jet  of  gas  and,  in  a  measure,  dilute 
the  outer  zone  of  this  gas  so  that  the  portion  of  it  in  contact 
with  the  burner  is  not  sufficiently  rich  to  deposit  carbon,  without 
introducing  enough  air  to  seriously  reduce  the  efficiency  of  the 
flame  in  candle-power.  To  this  type  of  burner  may  be  attributed 
the  reduction  in  candle-power  below  that  obtained  from  the  Bray 
fish-tail  burner,  but  by  this  form  of  burner  the  commercial  use 
of  the  gas  is  made  possible.  Two  jets  are  caused  to  impinge 
upon  one  another,  thereby  flattening  out  into  a  flat  flame. 

With  this  commercial  type  of  burner,  it  is  not  possible,  as 
before  stated,  to  obtain  50  candle-power  to  the  foot,  but  a  fair 
average  of  the  various  burners  now  manufactured  would  give  the 
following  results.  The  burners  here  referred  to  are  the  Von 
Schwarz  Perfection  burners. 


Burner 

Consumption 

Candle-power 

C.  P.  per  foot 

I    ft. 

1.036 

45.4 

44. 

V^  ft. 

.74 

30.0 

40.5 

/2   ft. 

.49 

16.8 

34.3 

Va  ft. 

.28 

4.9 

17.5 

With  the  use  of  an  incandescent  mantle  with  acetylene,  the 
candle-power  may  be  very  greatly  increased  per  cubic  foot,  but, 
up  to  the  present  time  in  the  United  States,  mantles  have  not 
been  brought  into  general  use  in  connection  with  this  gas,  as  its 
intrinsic  illuminating  power  is  so  high. 

At  the  present  time,  this  industry  covers  a  very  large  field. 
Acetylene  is  already  in  general  use  as  a  means  of  illuminating 
isolated  houses,  small  towns,  railroad  cars,  railroad  signals,  loco- 
motive headlights,  pleasure  yachts  and  all  kinds  of  harbor  craft, 
and  various  aids  to  navigation,  such  as  buoys,  beacons,  stake 
lights  and  large  shore  lights,  oxy-acetylene  welding,  and  auto- 
mobile headlights. 

Railroad   lighting   is   accomplished   by   means   of   compressed 


686  ENGINEERING   CHEMISTRY 

gas  stored  in  cylinders  filled  with  asbestos  and  saturated  with 
acetone,  said  cylinders  being  held  under  the  car  and  gas  piped 
through  a  suitable  reducing  valve  to  the  car  lamps  where  it  is 
burned  the  same  as  any  other  gas.  On  locomotives,  the  tank  is 
usually  placed  under  the  running  board  on  the  fireman's  side  and 
the  gas  pipe  to  a  headlight  equipped  with  a  parabolic  reflector, 
the  flame  being  located  at  the  focus.  The  boat  lighting  by  this 
method  is  much  the  same,  the  gas  being  piped  to  the  various  state- 
rooms and  there  burned  in  ordinary  fixtures. 

For  isolated  houses,  an  automatic  generator  is  used,  as  de- 
scribed in  the  earlier  part  of  this  paper,  the  generator  being  fed 
with  carbide  and  its  operation  being  governed  by  the  use  of  the 
gas  from  it.  Town  plants  are  operated  much  in  the  same  manner 
as  the  city  gas  plants,  a  central  generator  and  store  holder  being 
installed  and  the  gas  piped  from  this  store  holder  to  the  various 
parts  of  the  town. 

A  very  important  field  of  operation,  which  is  being  taken 
up  by  the  governments  of  all  the  different  countries,  is  the  light- 
ing of  navigation  signals  by  means  of  this  gas.  Fig.  136  shows 
one  type  of  buoy  extensively  used  in  Europe  in  connection  with 
the  absorbed,  or  dissolved,  gas  system.  The  gas  is  stored  in  the 
cylinder  at  the  extreme  bottom  of  the  drawing,  under  a  pres- 
sure of  ten  atmospheres,  and  is  piped  from  the  cylinder  through 
the  central  tubular  section  to  the  tower  and  the  lantern. 

The  floating  body  consists  of  a  steel  shell  made  up  of  a 
bumped  head  at  either  end  and  a  cylindrical  portion,  the  parts 
being  wielded  together  by  means  of  the  oxy-acetylene  torch,  which 
is  the  latest  development  in  the  acetylene  field.  On  this  particular 
type  of  buoy,  there  are  no  rivets,  all  the  joints  being  made  by  the 
use  of  the  torch  so  that  the  whole  buoy  is  virtually  one  solid 
shell  of  steel. 

A  buoy,  such  as  is  shown  on  Fig.  136,  contains  in  its  gas  reser- 
voir approximately  1,100  cubic  feet  of  acetylene  and,  with  a  flash 
characteristic  of  ^,  for  instance  one  second  of  light  and  four 
seconds  of  darkness,  would  run  continuously  without  recharging 
or  attention  for  a  period  of  275  days,  and  with  a  flash  character- 


E^NGINKERING   CHEMISTRY 


687 


istic  of  i/io  would  run  double  this  time,  or  550  days.     Various 
other  types  of  buoys  are  built  to  meet  different  requirements. 

Assuming  that  such  a  light  as  the  one  described  for  this  buoy 
is  to  be  placed  as  a  fixed  light  at  some  inaccessible  place,  saving 
in  gas  and  consequent  length  of  service  is,  therefore,  of  the  ut- 


Fig.  136. 

most  importance.  This  was  recognized  by  the  invention  of  what 
is  known  as  the  sun-valve,  or  a  device  which  automatically  closes 
off  the  gas  in  the  day  time  and  relights  it  at  night.  Fig.  137 
shows  this  apparatus. 

It  consists  of  three  polished,  silver-plated  rods  supporting  a 
frame  which  acts  upon  the  central  cylinder,  the  surface  of  which 


Fig.  137- 


I^NGINK^RING   CHEMISTRY  689 

is  coated  with  lampblack,  and  its  operation  is  based  upon  the 
fact  that  two  surfaces,  one  polished  and  the  other  dead  black,  will 
absorb  different  amounts  of  light,  or,  in  other  words,  the  one 
which  absorbs  the  light  rays  becomes  heated  to  a  greater  extent 
than  the  one  which  reflects  the  light  rays.  The  dark  one,  there- 
fore, expands  more  than  the  polished  one.  This  principle  was 
made  use  of  in  this  mechanism  in  that  the  expansion  and  con- 
sequent lengthening  of  the  black  cylinder  causes  the  closing  of 
the  vale  'J"  on  the  seat  ''g."  (Fig.  137.)  On  a  sunshiny  day, 
this  action  immediately  takes  place  and  the  setting  of  the  sun 
brings  both  the  polished  and  the  black  elements  back  to  their 
original  condition  and  permits  the  free  flow  of  gas  to  the  lantern 
where  it  is  at  once  ignited  from  the  pilot  flame  which  burns  con- 
tinuously. It  has  been  found  that,  in  latitudes  resembling  New 
York,  the  saving  accomplished  by  such  a  device  is  approximately 
40  per  cent.,  or,  in  other  words,  the  light  just  described  which 
without  the  sun-valve  and  utilizing  a  flash  characteristic  of  i/io 
light  and  9/10  darkness,  runs  for  550  days,  would  by  the  use  of 
the  sun-valve  run  915  days  continuously. 

Oxy-acetylene  Welding. — The  exceedingly  high  temperatures 
obtainable  by  the  use  of  oxygen  and  acetylene  have  been  utilized 
in  the  welding  of  steel.  This  is  accomplished  by  means  of  a 
torch,  many  types  of  which  exist  at  the  present  time,  in  which 
both  gases  are  led  to  a  common  nozzle  and  there  mixed  in  the 
correct  proportions  and  pressure  so  as  to  form,  in  burning,  an 
arc  of  white  flame  w^hose  temperature  ranges  from  5,600°  F.  to 
6,300°  F.  The  velocity  of  the  gas  in  leaving  the  tip  is  such  that 
the  tip  itself  does  not  burn  off  or  melt,  but  this  small  cone  of 
flame  can  be  brought  down  and  impinged  directly  upon  the  two 
elements  which  are  to  be  united.  A  Swedish  iron  wire  filler  is 
used  and,  when  the  edges  are  brought  to  the  welding  heat,  this 
wire  is  fed  in  and  melted  in  the  same  manner  as  solder  would 
be,  thus  forming  an  absolute  homogeneous  and  powerful  union 
of  the  two  pieces.  An  oxy-acetylene  weld,  when  properly  made, 
will  run  as  high  as  90  per  cent,  of  the  original  strength  of  the 
plate,  and  with  pure  gas  and  the  proper  torch,  this  class  of  work 
can  be  done  far  more  rapidly  by  this  method  than  by  any  other. 
44 


690  ENGINEJERING   CHEMISTRY 

These  same  torches  are  usually  supplied  with  a  cutting  at- 
tachment which  consists  in  first  applying  the  heating  flame  and 
raising  the  temperature  of  that  portion  of  the  steel  to  be  cut  to 
a  white  heat.  As  soon  as  this  is  done,  a  high  pressure  auxiliary 
jet  of  oxygen  is  turned  on  to  the  white  hot  metal.  The  carbon  of 
the  steel  is  immediately  consumed  and,  in  a  way,  furnishes  the 
fuel  for  the  cutting.  A  high  pressure  jet  of  oxygen,  say  at  100 
to  150  pounds  pressure,  will  cut  through  3  inches  of  steel 
far  more  rapidly  than  a  saw  and  the  entire  cutting  and  welding 
equipment  can  be  carried  around  in  a  wheelbarrow\  The  con- 
venience of  this  system  has  led  to  its  use  in  difficult  places  and 
for  repair  work  on  automobiles  where  economy  of  time  is  requi- 
site. 

VALUATION  OF  COAL  FOR  THE  PRODUCTION  OF  GAS. 

Take  100  grams  of  the  coal  in  small  lumps,  so  that  they  may 
be  readily  introduced  into  a  rather  wide  combustion  tube.  This 
is  drawn  out  at  its  open  end  (after  the  coal  has  been  put  in  it)  so 
as  to  form  a  narrow  tube,  which  is  to  be  bent  at  right  angles; 
this  narrower  open  end  is  to  be  placed  in  a  wider  glass  tube, 
fitted  tightly  into  a  cork  fastened  into  the  neck  of  a  somewhat 
wide-mouthed  bottle  serving  as  tar  vessel.  The  cork  alluded  to 
is  perforated  with  another  opening  wherein  is  fixed  a  glass  tube 
bent  at  right  angles,  for  conveying  the  gas,  first  through  a  cal- 
cium chloride  tube,  next  through  L^iebig's  potash  bulbs  contain- 
ing a  solution  of  caustic  potash,  having  lead  oxide  dissolved  in  it. 
Next  follows  another  tube  partially  filled  with  dry  caustic  potash 
and  partly  with  calcium  chloride;  from  this  last  tube  a  gas- 
delivery  tube  leads  to  a  graduated  glass  jar  standing  over  a  pneu- 
matic trough,  and  acting  as  gas-holder.  Before  the  ignition  of 
the  tube  containing  the  coal  is  proceeded  with,  all  the  portions  of 
the  apparatus  are  carefully  weighed  and  next  joined  by  means 
of  India-rubber  tubing.  After  the  combustion  is  finished,  which 
should  be  carefully  conducted  so  as  to  prevent  the  bursting  or 
blowing  out  of  the  tube,  the  different  pieces  of  the  apparatus  are 
disconnected  and  weighed  again.  The  combustion  tube  has  to 
be  weighed  with  the  coal  after  it  has  been  drawn  out  at  its  open 


ENGINEERING   CHEMISTRY  691 

end,  and  with  the  coke  after  the  end  of  the  combustion,  when  it 
is  again  cold,  and  for  that  reason  care  is  required  in  managing 
it.  We  thus  get  the  quantity  of  coke,  tar,  ammoniacal  water, 
carbon  dioxide,  and  hydrogen  sulphide  (as  lead  sulphide),  and 
the  gas  is  measured  by  immersing  the  jar  in  water,  causing  it  to 
be  at  the  same  level  inside  and  out. 

Empty  the  Liebig's  bulbs  into  a  beaker  and  separate  the  lead 
sulphide  by  filtration,  wash  well,  dry  and  weigh.  From  the  lead 
sulphide  the  hydrogen  sulphide  present  is  calculated.  This  pro- 
cess, devised  by  the  late  Dr.  T.  Richardson,  of  Newcastle-on- 
Tyne,  was  found  by  him  to  yield  very  reliable  results,  so  as  to  be 
suitable  for  stating  what  quantity  of  gas  a  ton  of  coal  thus  anal- 
ized  would  yield. ^ 

Newbigging's  Experimental  Plant  for  the  Determination 
of  the  Gas-Producing  Qualities  of  Coal. 

The  apparatus  consists  of  the  following: 

Retort. — Cast  iron,  5  inches  wide,  4.5  inches  high,  2  feet,  3 
inches  long  outside,  and  0.4  inch  thick. 

Ascension  Pipe. — 2-inch  wrought  tube. 

Connections. — 1.5  inch  wrought  tube. 

Condenser. — 12  vertical,  1.5  inch  wrought  tubes,  each  3  feet  6 
inches  long. 

Washer. — i  foot  long,  6  inches  wide,  and  6  inches  deep. 

Purifier. — i  foot  2  inches  square,  12  inches  deep,  with  2  trays 
of  lime. 

Gas-holder. — Capacity  12  cubic  feet,  with  graduated  scale  at- 
tached. 

Amount  of  coal  to  be  taken  for  each  test  i/iooo  part  of  a 
ton,  or  2.24  pounds.  Care  should  be  taken  to  obtain  a  fair  aver- 
age sample  of  the  coal  to  be  operated  upon.  For  that  purpose  at 
least  50  pounds  of  coal  should  be  broken  up  into  small  pieces  and 
thoroughly  intermixed,  and  from  this  three  different  charges  are 
to  be  taken.  The  retort  should  be  at  a  bright  heat  before  the 
introduction  of  the  coal  and  maintained  at  that  temperature  during 
the  test.    If  from  any  cause  the  temperature  is  much  reduced,  the 

1  Crookes'  "  Select  Methcxi  in  Chemical  Analysis,"  p.  607. 


692 


ENGINEERING    CHEMISTRY 


test  will  not  be  satisfactory.  The  time  required  to  work  off  the 
charge  of  2.24  pounds  will  range  from  forty  to  sixty  minutes, 
according  to  the  character  of  the  coal.     The  illuminating  power 


of  the  gas  given  out  from  each  charge  should  be  ascertained  by 
the  Bunsen  photometer,  no  other  being  sufficiently  trustworthy 
for  that  purpose.  The  average  of  the  three  is  then  taken,  both 
for  yield  of  gas  and  coke  and  for  the  illuminating  power  of  the 


ENGINEERING    CHEMISTRY  693 

gas,  and  this  fairly  represents  the  capabilities  of  the  coal.  The 
further  conditions  to  be  observed  are  that  the  holder  be  emptied 
of  air  or  of  the  previous  charge  of  gas,  and  that  the  condenser  be 
drained  of  its  contents.  The  test  charge  may  be  continued  until 
the  v^hole  of  the  gas  is  expelled,  or  otherwise,  depending  on 
circumstances.  In  comparing  two  coals,  an  equal  production 
from  both  may  be  obtained,  and  the  comparative  illuminating 
power  then  ascertained. 

The  coke  and  "breeze"  should  be  carefully  drawn  from  the 
retort  into  a  water-tight  receptacle  made  of  sheet  iron  closed 
by  a  lid.  This  is  then  placed  in  a  bucket  or  other  vessel  of  cold 
water,  and  when  sufficiently  cooled,  the  coke  is  weighed. 

For  ascertaining  the  quantity  of  tar  and  ammoniacal  liquor 
produced,  drain  the  yield  of  three  charges  from  the  condenser 
and  washer  and  measure,  this  in  a  graduated  liquid  measure.  The 
number  of  fluid  minims  in  a  gallon  (English)  is  76,800.     Then: 

Pounds.  Pounds  per  ton. 

^  ^,  ,         r  ^        r  The  total  num-  ^ 

(The  weight  of  ^  nl^mrortar  '     ber  of  minims     I 

6.75      three  charges       :  2240  :  ^  ZlTc^uol  ob-  ]  '    ]  ^'il'^li'l^T  \ 
[        of  coal  J  'j^         ^^^^^^         J  from^a^tonof    J 

and  this  amount  divided  by  76,800  gives  the  gallons  of  tar  and 
liquor  produced  per  ton.  A  good  variety  of  gas  coal  should  pro- 
duce from  2,240  pounds  of  coal  12,000  cubic  feet  of  gas,  illumi- 
nating power  20  sperm  candles. 

Newcastle  coal  on  an  average  produces  12,700  cubic  feet  of 
gas  per  ton  of  coal,  illuminating  power  of  15  sperm  candles. 

As  an  example  of  the  method  of  determining  the  value  of  a 
rich  cannel  coal  for  production  of  gas  and  coke,  the  results  of  a 
working  test  upon  1,196  pounds  of  coal,  made  by  the  writer, 
are  given  herewith. 

The  analysis  of  the  coal  gave  the  following  percentages : 

Per  cent. 

Moisture  at  103°  C.   (>4  hour) 1.31 

Volatile  and  combustible  matter  (ignition,  7  mmutes)  . .   57-99 

Fixed  carbon   28.36 

Sulphur   (KNO3  -f  NaaCOs  fusion) 2.54 

Ash    979 

Total   99.99 


694 


ENGINEERING   CHEMISTRY 


The  testing  plant  was  especially  designed  and  arranged  for 
trials  of  this  character,  having  a  capacity  for  each  charge  of 
250  pounds  of  coal. 

The  coke  produced  was  as  follows  * 


Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

Coal    

224 

94 

68 

224 
98 

224 
97 

150 

67 

224 

98 

Or>V*»  rjmfl  npffl . 

or  the  coal  produced  43.3  per  cent,  of  coke.  Theoretically,  from 
the  analysis  of  the  coal,  the  amount  of  coke  that  could  be  pro- 
duced would  be  44.2  per  cent.,  a  difference  of  0.9  per  cent. 

The  coke,  as  shown  by  analysis,  was  composed  as  follows : 

•  Per  cent. 

Moisture 1.30 

Volatile  and  combustible  matter  2.24 

Fixed  carbon   79-82 

Sulphur    1.83 

Ash    14.81 


Total 100.00 

The  amount  of  coal  gas  produced  from  the  1,196  pounds  of 
cannel  coal  was  as  follows : 


Coal 
Pounds 


150 
224 
224 
150 
224 
224 


Gas  produced 
Cubic  feet 


789.7 

i,in.o 
1,156.0 

759-9 
1 ,090,0 
1,160.0 

6,066.6 


Equivalent 
per  lone  ton 

(2,240  lbs.) 


I '.793 
II, 1 10 
11,560 

11,349 
10.900 
11,600 

68,302 


or  at  the  rate  of  11,384  cubic  feet  per  ton  of  2,240  pounds,  the 
gas  having  a  candle-power  of  36. 


ENGINEERING   CHEMISTRY  695 

MANUFACTURE  OF  OIL  GAS. 

Oil  gas  is  usually  formed  by  vaporization  of  mineral  oil  at  high 
temperatures.  Two  processes  are  in  use:  the  "Pintsch"  and  the 
**Keith/'  the  former  probably  representing  90  per  cent,  of  the 
production  of  oil  gas. 

In  the  manufacture  of  Pintsch  oil  gas,  in  the  United  States, 
"mineral  seal"  oil  is  often  used.  This  oil  is  a  petroleum  product 
having  a  specific  gravity  of  about  0.840,  flashing-point  266°  F., 
and  fire  test  311°  F. 

Several  analyses  of  this  oil,  by  the  author,  give  carbon  83.30 
per  cent.,  hydrogen  13.20 -per  cent.,  the  remainder  being  oxygen, 
nitrogen,  etc.,  and  the  analysis  of  the  gas  therefrom  gave: 

per  cent. 

CO    0.5 

CH.  57.7 

H 34 

r  Benzene  vapor,  CgHg  '\ 
Illuminants   }  Propylene  CgHg  [    38.  i 

(  Ethylene  CjH^  ) 

The  heating  power  would  indicate  1,390  B.  t.  u.  per  cubic  foot, 
products  condensed. 

W.  Ivison  Macadam,  F.  C.  S.,  tabulates  the  results  of  a  series 
of  his  tests  upon  the  Pintsch  and  Keith  oil  gas  as  follows : 

Paraffin  Oii,  Into  Gas 


Specific  gravity  of  the  oil 

Weight  of  I  gallon  of  the  oil 

Number  of  gallons  per  ton  of  oil 

Flashing-point    

Burning-point 

Gas  from  i  gallon  of  oil 

Gas  from  i  ton  of  oil 

Candle-power  of  gas 

Illuminating  value  of  i  cubic  foot  in 

grains  of  sperm 

Illuminating  value  of  i  ton  in  lbs.  of  sperm 


Average  of  trials 

Average  of  trials 

with  Keith's 

with  Pintsch's 

apparatus. 

Apparatus. 

0.875 

0.877 

8.758  lbs. 

8.779  lbs. 

255.76 

255-15 

289°  F. 

295°  F. 

347°  F. 

354°  F. 

84.93  cu.  ft. 

90.03  cu.  ft. 

21,720  cu.  ft. 

24,757  cu.  ft. 

61.38  candles. 

60.82  candles 

1.473  grains 

1,459  grains 

4,570  lbs. 

5,160  lbs. 

696  ENGINKDRING   CHEMISTRY 

The  Manufacture  of  Pintsch  Gas,  Its  Distribution  and  Uses. 

By  R.  Vi.iii<i.EUMiER, 
Chief  Engineer,  Pintsch  Compressing  Company,  New  York. 

Pintsch  gas  is  obtained  by  the  destructive  distillation  of  petro- 
leum or  some  of  its  distillates.  Since  it  is  a  fixed  gas  under  ordi- 
nary temperatures  and  pressures  and  is  rich  in  heavy  hydrocar- 
bons of  a  low  boiling  point  the  gas  is  exceptionally  well  suited 
for  compression.  Pintsch  gas  when  compressed  to  15  atmos- 
pheres absolute  pressure  loses  only  about  10  per  cent,  of  its 
illuminating  value  in  the  open  flame,  while  coal  gas,  known  as 
"city  gas,"  when  compressed  loses  its  illuminating  value  to  a  far 
greater  extent.  This  characteristic  feature  renders  Pintsch  gas 
particularly  available  as  a  portable  illuminant  for  the  lighting  of 
railroad  coaches,  light-houses,  buoys,  beacons,  etc. 

A  large  number  of  Pintsch  plants  are  distributed  over  the  en- 
tire North  American  continent,  and  supply  Pintsch  gas  to  practi- 
cally all  railroads  of  the  United  States,  Canada,  and  Mexico,  as 
well  as  a  large  quantity  to  the  various  light-house  departments  of 
these  countries  for  coast  lighting.  There  are  in  addition  many 
transport  stations  to  aid  in  the  distribution  of  the  gas.  Com- 
pressed gas  from  a  Pintsch  generating  plant  is  transported  by 
rail  in  large  '"storeholders,"  cylindrical,  steel-welded  tanks,  or  in 
seamless  high  pressure  cylinders,  to  the  transport  stations  where 
the  gas  is  distributed  through  the  necessary  pipe  line  systems  to 
railroad  stations  and  coach  yards. 

Originally  Pintsch  gas  was  produced  in  the  retort  furnaces 
patented  by  Julius  Pintsch,  of  Berlin.  These  contained  two  cast 
iron  retorts  mounted  one  above  the  other,  with  the  object  of 
vaporizing  the  oil  in  the  upper  retort,  and  then  conducting  the 
vapor  through  the  lower  and  more  highly  heated  retort  to  accom- 
plish the  cracking  of  the  vapor  into  the  desired  gaseous  form. 
American  practice,  however,  soon  found  a  decided  advantage  in 
the  substitution  of  clay  retorts  of  larger  size  and  greater  number 
to  one  furnace,  for  this  permitted  a  production  on  a  larger  scale 
with  less  interference  from  the  burning  out  of  the  retorts,  and  in- 
cidentally with  less  expense  on  account  of  renewals,  etc.     Figs. 


Engine;e;ring  chemistry 


697 


ENGINEERING   CHEMISTRY 


139  and  140  illustrate  a  Pintsch  plant  which  has  been  modified  in 
accordance  with  American  practice. 

Fig.  140  shows  the  ground  plan  of  the  building  which  is  divided 
into  two  rooms,  vis. :  the  furnace  room,  compressing  room  and 
purifying  room.  The  latter,  forming  the  second  story  above 
the  compressing  room,  does  not  appear  on  the  plan.  It  also 
shows  the  gas  holder  which  serves  as  storage  for  the  gas  under 
low  pressure,  while  the  compressed  gas  is  stored  in  a  battery  of 
from  ten  to  twenty  "storeholders"  also  shown  on  the  plan,  each 
of  a  capacity  of  265  cubic  feet  per  atmosphere. 


Fig.  140. 

The  oil  supply  is  stored  underground  in  cylindrical  tanks  of 
7,000  gallons  capacity  each.  The  tanks  are  hermetrically  sealed 
and  are  supplied  on  top  with  i-inch  gas  connection  from  the 
low  pressure  gas  holder,  providing  a  direct  communication  be- 
tween oil  and  gas,  so  that  the  air  is  absolutely  excluded  from  the 
oil  storage  tanks.  This  arrangement  prevents  the  formation  of 
an  explosive  mixture  in  the  tanks  and  effectively  eliminates  all 
danger  from  fire  or  explosion.  Tanks  of  same  description,  sim- 
ilarly located  and  connected,  serve  for  the  storage  of  the  by- 
products, "Pintsch  tar"  and  "Pintsch  hydrocarbon." 

Fig.  139  shows  in  diagrammatic  form  the  arrangement  of  the 
apparatus  inside  the  building.  The  oil  is  pumped  into  the  oil 
supply  tank  located  in  the  furnace  room  from  where  it  flows  by 


ENGINEE^RING   CHE^MISTRY  699 

gravity  through  the  regulating  cocks  and  oil  cups  to  the  retorts. 
These  retorts  are  built  of  clay,  3  inches  thick  and  are  of  D  sec- 
tion. The  ends  are  fitted  with  cast  iron  mouthpieces  with  self 
sealing  lids.  Each  furnace  is  equipped  with  six  retorts  placed  in 
three  tiers,  two  wide.  The  furnaces  are  of  the  recuperative  type 
and  are  heated  with  coal  or  coke.  Deep  firing  is  practiced  in  this 
style  of  furnace,  with  the  object  of  generating  producer  gas  in 
the  fire  box.  Primary  air  for  the  partial  combustion  and  gasifi- 
cation of  the  fuel,  is  admitted  through  the  grate  bars.  A  pre- 
heated secondary  air  supply  mingles  with  the  partial  products  of 
combustion  given  off  by  the  fire  box  and  completes  the  combus- 
tion in  the  retort  setting,  producing  a  high  temperature.  The 
resultant  total  products  of  combustion  are  conducted  over  the 
retorts  and  serve  finally  to  preheat  the  secondary  air  supply  be- 
fore reaching  the  stack. 

The  oil  on  entering  the  retorts  through  the  mouthpiece,  does 
not  come  in  contact  with  the  clay  but  is  conducted  through  a 
wrought  iron  vaporizing  pipe.  It  is  thus  intensely  heated  and 
reaches  the  retort  proper  in  the  form  of  vapor.  In  order  to  reach 
the  outlet  of  the  retort,  the  vapor  has  to  travel  through  its  entire 
length,  but  this  time  in  contact  with  the  intensely  heated  clay 
retort. 

The  working  temperature  of  the  retorts  varies  from  1,100°  to 
1,600°  F.  Temperatures  above  this  have  a  detrimental  effect 
upon  the  quality  of  the  gas,  while  lower  temperatures  do  not 
satisfactorily  gasify  or  fix  the  oil  vapor.  A  comparatively  hot 
retort  will  gasify  satisfactorily  a  larger  stream  of  oil  than  is  the 
case  with  a  less  hot  retort.  The  flow,  of  oil,  therefore,  must  be 
carefully  gauged  to  suit  the  temperature  of  each  retort.  Frequent 
tests  of  the  fresh  gas  are  performed,  which  guide  the  gas  maker 
in  his  work.  A  small  jet  of  the  fresh  gas  issuing  from  the  retort, 
will  leave  a  stain  upon  a  bright  metallic  surface  or  clean  paper, 
from  which  the  richness  of  the  gas  can  be  readily  determined.  A 
test  flame  in  the  furnace  room  burning  fresh  gas,  serves  to  give 
additional  information  to  the  experienced  eye  of  the  gas  maker. 
In  order  to  keep  a  final  check  on  the  finished  and  compressed 
product,  the  plant  is  equipped  with  a  photometer  room  where  the 


/OO  IvNGINI^E:rING   CIIEJMISTRY 

exact  candle-power  of  the  gas  is  determined  by  means  of  a  bar 
photometer. 

The  gas  leaves  the  retorts  through  6-inch  vertical  cast  iron 
pipes  which  are  attached  to  the  mouth  pieces  and  connect  each 
retort  to  the  hydraulic  main  on  top  of  the  furnace.  The  entrance 
of  the  gas  into  the  hydraulic  main  is  effected  through  dip  pipes 
which  dip  about  ^  inch  below*  the  surface  of  the  tar  in  the 
hydraulic  main.  This  prevents  gas  passing  from  one  retort  to 
another,  and  permits  the  opening  for  cleaning  of  any  of  the  re- 
torts while  others  are  making  gas.  That  part  of  the  oil  vapor 
which  recondenses  as  oil  tar  is  collected  in  the  tar  storage  tanks 
above  mentioned.  Cool  tar  from  the  tar  storage  tanks  is  con- 
stantly circulated  by  means  of  a  steam  pump,  through  the  hydrau- 
lic main  to  prevent  the  overheating  of  the  tar  in  the  main. 

The  gas  leaves  the  hydraulic  main  through  a  large  take-off  pipe 
and  reaches  the  purifying  room,  where  it  first  passes  through  a 
condenser,  resembling  a  vertical  tubular  boiler  in  construction. 
It  travels  through  the  tubes  of  the  condenser  which  are  exter- 
nally cooled  by  means  of  water  circulation.  This  effects  the 
cooling  of  the  gas  and  removes  a  large  quantity  of  tar  by  conden- 
sation. Then  the  gas  is  conveyed  through  the  washer  containing 
a  large  diaphram  with  downward  projecting  ribs,  slightly  sub- 
merged below  the  surface  of  the  tar.  Under  this  diaphragm  the 
gas  is  conducted  and  is  there  divided  into  thin  films  coming  into 
intimate  contact  with  the  tar.  This  process  effects  the  removal 
of  tar  vapor  and  of  solid  particles  which  the  gas  still  holds  in 
suspension  after  leaving  the  condenser. 

The  gas  passes  then  into  the  purifiers  for  the  removal  of  the 
sulphur  impurities,  such  as  sulphurated  hydrogen,  etc.  These 
purifiers  are  large  cast  iron  boxes  provided  with  water-sealed 
covers.  Gas  connections  are  so  arranged  that  the  gas  enters  the 
purifier  near  its  bottom  and  passes  upward  through  a  series  of 
trays  covered  with  air-slaked  lime  or  oxide  of  iron.  A  test  cock 
provided  in  the  cover  on  the  top  of  each  purifier  serves  for  test- 
ing the  purified  gas.  A  small  jet  of  gas  impinging  upon  a  piece 
of  white  paper  moistened  with  a  saturated  solution  of  acetate  of 
lead,  will  at  once  indicate  the  presence  of  any  sulphur  impurity 


ENGINEERING   CHEMISTRY  /OI 

by  discoloring  the  paper.  The  finished  low-pressure  gas  is  then 
conveyed  through  a  large  station  meter  to  the  relief  holder,  a  gas 
holder  of  a  type  similar  to  that  found  in  connection  with  city 
gas  works. 

Each  of  the  above  mentioned  apparatus  from  the  take-off  pipe 
at  the  retorts  to  the  relief  holder,  offers  a  resistance  to  the  flow 
of  gas,  and  under  normal  working  conditions  it  is  found  that  a 
pressure  of  about  9  inches  of  water  is  required  to  overcome  the 
sum  of  all  resistance.  A  pressure  of  this  magnitude  falling  upon 
the  clay  retorts  would  cause  considerable  leakage  of  gas  through 
the  clay,  and  in  order  to  relieve  the  pressure  a  steam  driven  rotary 
pump  or  "exhauster"  is  introduced  with  a  sensitive  pressure  reg- 
ulating valve  which  controls  its  speed  in  accordance  with  the 
amount  of  gas  made  and  thus  constantly  preserves  a  pressure  of 
about  I  inch  of  water  on  the  retorts.  Each  apparatus  is  connected 
by  means  of  a  ^-inch  pipe  to  a  glass  of  the  "differential  gauge,"  a 
multiple  water  gauge,  and  any  fluctation  of  pressure  from  the 
normal,  due  to  stoppage,  etc.,  in  any  part  of  the  system  can  be 
readily  observed  and  the  cause  located. 

The  next  and  last  step  in  the  manufacture  of  the  gas  is  com- 
pression. This  is  accomplished  by  steam  driven  compressors  es- 
pecially designed  and  built  for  this  purpose  by  the  Pintsch  Com- 
pressing Company  of  New  York,  as  the  outcome  of  long  exper- 
ience. These  compressors  are  compound  steam,  single  or  two- 
stage  gas,  straight  line  machines.  They  are  extremely  simple  in 
design  and  very  efficient  in  operation.  The  steam  distribution  of 
both  steam  cylinders  is  effected  by  semi-rotary  pattern  valves 
positively  driven  by  a  single  eccentric.  The  gas  cylinders  are 
equipped  with  easily  accessible  valves  of  the  automatic  poppet 
type,  arranged  to  reduce  clearance  losses  to  a  minimum.  The 
cylinder  and  cylinder  heads  are  carefully  water  jacketed  and  an 
inter-cooler  of  ample  proportions  is  inserted  between  the  low  and 
high  pressure  cylinders,  so  that  an  effective  approximation  to 
ideal  isothermal  compression  is  reached. 

Provisions  are  made  to  separate  and  remove  the  condensation 
"hydrocarbon"  which  is  caused  by  compression  in  the  low  pres- 
sure cylinder  before  it  reaches  the  high  pressure  cylinder;  and 


702  ENGINEEJRING   CHEMISTRY 

its  detrimental  influence  upon  the  compressor  and  packing  is  thus 
removed.  The  compressors  take  the  low  pressure  gas  from  the 
relief  holder  through  a  separate  outlet  and  compress  it  to  about 
15  atmospheres  absolute  pressure.  Condensation  of  "hydrocar- 
bon," consisting  of  light  oils,  is  obtained  from  both  stages  of  the 
compression  after  the  gas  has  been  cooled,  and  a  corresponding 
reduction  in  volume  is  thus  experienced.  The  compressors  dis- 
charge the  gas  through  after-coolers  into  the  "storeholders"  above 
described. 

The  "storeholders"  are  connected  in  series,  so  that  the  gas 
has  to  pass  through  one  after  the  other  before  reaching  the  pipe 
line.  This  effects  additional  cooling  and  deposits  any  hydrocar- 
bon vapor  held  in  suspension  before  the  gas  leaves  the  plant. 
Each  storeholder  is  provided  with  a  drain  for  the  removal  of  the 
hydrocarbon,  through  which  it  is  conveyed  to  the  hydrocarbon 
draw-off  can,  an  apparatus  which  effects  the  separation  between 
liquid  and  vapors  that  effervesce  as  soon  as  the  pressure  upon 
the  hydrocarbon  is  relieved.  The  vapors  are  conducted  to  the 
gas  holder  while  the  liquid  is  collected  in  the  hydrocarbon  storage 
tanks. 

A  high  pressure  pipe  line  connected  to  the  outlet  of  the  last 
storeholder,  conveys  the  gas  to  the  various  coach  yards  or  rail- 
road stations  where  a  large  network  of  pipe  distributes  the  gas  to 
filling  valves  located  in  the  ground  between  tracks.  For  example, 
the  new  terminal  station  and  coach  yard  at  Washington,  D.  C, 
contains  a  network  of  8//^  miles  of  pipe  with  678  filling  valves. 
These  filling  valves  are  arranged  so  that  any  car,  irrespective  of 
its  location,  can  be  reached  by  50  feet  of  gas  hose.  All  gas  hose 
is  provided  with  special  fittings  for  quick  attachment  and  release, 
so  that  but  a  few  minutes  are  consumed  for  the  gassing  of  an 
entire  train,  which  in  most  cases  is  accomplished  while  the  train 
is  making  one  of  its  regular  stops  at  a  station. 

During  the  last  decade  the  Pintsch  process  in  America  has 
undergone  marked  improvements.  The  retort  furnaces  have  been 
superseded  by  internally  heated  generators  of  a  type  similar  to 
the  apparatus  used  in  carbureted  water  gas  practice,  excepting 
that  the  Pintsch  generating  apparatus  consists  of  but  a  single 


ENGINEERING    CHEMISTRY  703 

shell.  The  generator  is  intermittently  heated  by  means  of  a  liquid 
fuel,  each  heating  period  being  followed  by  a  gas-making  period. 
The  quality  of  the  Pintsch  gas  made  in  these  generators  is  under 
perfect  control.  A  generator  of  large  size  has  an  output  equal  to 
that  of  sixty  of  the  original  Pintsch  retort  furnaces. 

In  the  year  1901  the  Pintsch  Compressing  Company  of  New 
York  took  up  the  cracking  or  gasification  of  mineral  oils  under 
high  pressure,  and  located  a  plant  at  Shreveport,  La.,  to  serve  the 
various  railroads  entering  that  city.  The  gas  for  this  purpose 
was  generated  under  15  atmospheres  absolute  pressure  in  strong 
iron  retorts  of  small  diameter.  This  high  pressure  retort  process 
was  superceded  in  about  1905  by  a  high  pressure  generator  pro- 
cess, and  several  plants  were  installed  in  the  United  States  and 
Canada,  in  which  the  gas  is  manufactured  under  a  pressure  of 
15  atmospheres  absolute  on  generators  of  considerable  size. 
After  undergoing  cooling,  scrubbing  and  purification  at  this  same 
pressure  the  gas  is  conveyed  directly  to  the  "storeholders"  for 
distribution.  In  this  process  the  necessity  of  compression  is  en- 
tirely eliminated  and  the  plants  are  consequently  simpler  and  more 
compact  in  construction. 

Whereas  Pintsch  gas  was  distributed  formerly  under  pressures 
not  exceeding  15  atmospheres  absolute,  within  the  last  decade 
the  distributing  pressure  has  in  some  cases  been  increased  to  as 
high  as  150  atmospheres.  This  opened  a  larger  radius  of  dis- 
tribution and  wider  application.  An  especially  rich  Pintsch  gas 
is  now  used  for  industrial  and  domestic  heating  and  lighting  pur- 
poses, and  is  sold  under  the  name  of  "Isolite." 

Pintsch  gas  has  been  most  successfully  introduced  for  metal 
cutting  in  connection  with  oxygen,  likewise  for  lead  burning.  Its 
high  calorific  value,  united  with  its  exceptional  stability  and 
safety,  give  the  gas  a  marked  superiority  for  high  temperature 
flame  work  or  wherever  a  transportable  illuminating  and  heating 
gas  comes  under  consideration. 

Car  Equipment. 

By  George  E.  Hulse,  M.  E.,  Chief  Engineer  Safety  Car  Heating  and  Lighting  Company. 

Each  car  is  provided  with  one  or  more  welded  steel  holders  for 


704  ENGINEEJRING   CHEMISTRY 

carrying  the  compressed  gas.  These  holders  are  generally  9  feet 
6  inches  long  by  20  inches  in  diameter  and  hold  21.2  cubic  feet 
per  atmosphere.  A  car  has  a  storage  capacity  of  212  cubic  feet 
of  gas  for  each  holder  as  the  holders  are  ordinarily  filled  to  a 
gauge  pressure  of  10  atmospheres.  Each  car  is  provided  with 
two  filling  valves,  one  for  each  side,  and  a  pressure  gauge  so 
placed  as  to  be  easily  read  by  the  car  filler.  Each  holder  is  pro- 
vided with  a  T-shaped  holder  valve.  One  side  of  this  valve 
connects  to  the  filling  valve  and  the  other  side  to  the  high  pres- 
sure side  of  the  regulator.  In  case  of  emergency  this  valve  can 
be  closed,  to  shut  off  the  flow  of  gas  from  its  holder.  All  high 
pressure  fittings  are  extra  heavy,  of  brass,  and  the  joints  between 
the  fittings  and  the  pipe  are  screwed  and  soldered.  All  unions 
are  flanged  with  lead  gaskets. 

In  order  to  reduce  the  high  pressure  at  which  the  gas  is  stored 
to  a  pressure  suitable  for  use  in  the  lamps,  a  regulator  is  used. 
The  outlet  pressure  of  the  regulator  differs  with  the  kind  of  lamp 
used.  Regulators  on  cars  with  flat  flame  lamps  are  set  at  a  pres- 
sure of  1. 1 5  ounces  per  square  inch;  those  in  cars  with  incandes- 
cent mantle  lamps  at  either  i  pound  or  2  pounds  per  square 
inch,  according  to  the  size  of  the  mantle  used.  These  regulators 
are  simple  in  construction,  but  experience  has  shown  that  they 
are  very  reliable.  They  maintain  a  constant  outlet  pressure  with 
any  variations  of  inlet  pressure  and  consumption  which  occur  in 
service.  From  the  outlet  of  the  regulator  the  gas  is  carried 
through  a  5^ -inch  pipe  along  the  bottom  of  the  car  to  a  riser, 
extending  to  the  roof.  The  main  cock  is  placed  in  this  riser. 
When  closed  this  cock  shuts  off  the  supply  of  gas  from  all  the 
lamps.  The  gas  is  carried  to  the  lamps  by  a  ^^-inch  roof  line, 
from  which  branches  are  taken  off  to  each  lamp.  The  supply 
of  gas  to  each  lamp  is  controlled  by  a  lamp  cock. 

Ordinarily  the  cars  are  lighted  by  the  use  of  center  lamps  sus- 
pended from  the  upper  deck  for  general  illumination,  and  bracket 
lamps  placed  on  the  side  deck,  sides  of  bulkheads,  for  special 
illumination.  Experience  has  demonstrated  that  this  is  the  best 
method  to  eliminate  shadows  and  obtain  a  pleasing  illumination. 
With  flat  flame  lamps  clear  glass  bowls  are  used,  as  the  intensity 


ENGINEERING    CHEMISTRY  705 

of  the  flame  is  not  high  enough  to  have  a  bad  effect  on  the  eyes. 
With  mantle  lamps  either  ground  or  opal  globes  are  used,  and  give 
excellent  illumination  with  very  low  intensity  of  light  sources. 

The  flat  flanie  lamps  are  regenerative,  using  a  special  union  jet 
burner  and  are  draft  proof.  They  give  from  ten  to  twelve  candles 
light  per  cubic  foot  of  gas  consumed,  and  burn  from  3  to  4 
cubic  feet  per  hour.  This  type  of  lamp  has  to  a  great  extent, 
been  superseded  by  the  incandescent  mantle  lamp  of  the  inverted 
type,  using  a  mantle  especially  made  to  withstand  the  vigor  of 
railroad  service,  and  to  give  an  average  life  of  three  months. 
Two  sizes  of  mantles  are  used ;  the  smaller  gives  28  candle-power 
each,  with  a  gas  consumption  of  0.85  cubic  foot  per  hour  and  is 
used  for  bracket  lamps  and  in  center  lamps  in  clusters  of  two, 
three,  or  four ;  the  larger  mantles  give  100  candle-power  and  use 
2.12  cubic  feet  per  hour,  and  are  used  singly  in  center  lamps. 
The  light  distribution  from  inverted  mantles  is  such  that  reflec- 
tors or  prismatic  shades  are  unnecessary.  On  account  of  the  con- 
stant pressure  and  quality  of  Pintsch  gas,  and  because  the  gas  is 
entirely  free  from  vapors,  these  lamps  do  not  have  the  defects  of 
mantle  lamps  that  have  to  contend  with  insufficiency  and  variation 
of  the  supply  of  pressure. 

PRACTICAL  PHOTOMETRY. 

The  illuminating  value  of  any  source  of  light  is  determined  by 
comparing  it  with  some  source  of  light  of  known  value.  The 
illuminating  value  of  gas  is  measured  by  comparing  a  flame  that 
is  burning  at  the  rate  of  5  cubic  feet  an  hour  with  a  standard 
sperm  candle  that  is  burning  at  the  rate  of  120  grains  an  hour. 

The  amount  of  light  received  by  any  object  will  vary  inversely 
as  the  square  of  the  distance  of  that  object  from  the  source  of 
illumination,  hence,  if  the  light  whose  power  is  to  be  determined 
illuminates  a  body  at  x  inches  to  the  same  degree  that  a  standard 
candle  would  illuminate  that  same  body  at  y  inches,  the  illumi- 

Dating  power  of  that  light  will  be— ^  candles. 

In  constructing  a  photometer  this  single  principle  is  kept  in 
view,  and  all  the  refinements  are  to  eliminate  errors  in  judgment 
45 


7o6  ENGINEEJRING   CHEMISTRY 

and  to  allow  for  the  variations  in  the  rate  of  combustion  of  gas 
and  sperm. 

The  accompanying  illustration  (Fig.  141)  shows  the  form  of 
photometer  known  as  the  Bunsen,  which  is  the  one  commonly 
used  in  Germany,  England,  and  America. 

It  consists  first  of  a  table  which  carries  the  apparatus  and  on 
which  the  distance  between  the  lights  is  accurately  laid  off  and 
marked  by  two  lines.  This  distance  is  generally  60  inches,  but 
2  meters  and  icx>  inches  are  also  used.  In  case  either  light  is 
changed  or  moved  for  any  reason,  it  may  easily  be  put  back  in 
place  by  placing  it  centrally  over  the  line  indicated  on  the  table. 
To  facilitate  the  adjustment,  2  plumb-bobs  are  hung  over  each  of 
the  lines  at  the  ends  of  the  table,  so  it  is  easy  to  see  whether  the 
flames  are  properly  centered  in  one  direction.  In  the  other  direc- 
tion they  are  centered  by  sighting  along  the  bar.  The  bar  is  placed 
at  right  angles  to  the  two  lines  laid  out  on  the  table  and  cen- 
trally between  them.  It  is  laid  out  in  inverse  squares  so  that 
**i"  is  in  the  center.     If  the  length  of  the  bar  is  y  and  the  dis- 

(  y  xY 

tance  from  the  candle  is  x,  the   candle-power  is  ^ — —.      The 

mark  that  indicates  4  candle-power  is  twice  as  far  from  the  light 
to  be  measured  as  it  is  from  the  candle,  9  is  three  times  as  far,  etc. 
The  bar  should  be  made  so  that  it  may  be  raised  or  lowered  at 
pleasure,  and  be  planed  to  a  thin  edge  on  top  so  that  no  light 
will  be  reflected  from  it  on  the  disk.  On  the  bar  is  a  sight-box 
in  which  a  paper  disk  is  placed  at  right  angles  to  and  centrally 
over 'the  bar.  There  are  several  kinds  of  disks  used,  but  the  one 
most  commonly  preferred  in  this  country  is  made  by  taking  a 
piece  of  white  sized  paper  of  medium  thickness,  and  cutting  out 
of  the  center  a  many- pointed  star  about  i^  inches  in  diameter 
outside  the  points.  This  paper  with  the  star  cut  from  the  center 
is  then  placed  between  two  pieces  of  tissue  paper  and  the  three 
held  together  either  by  placing  between  pieces  of  glass  or  else  by 
being  fastened  with  thin  starch  water.  At  the  back  of  the  sight- 
box  are  two  mirrors,  so  placed  that  the  observer  may  stand  in 
front  of  the  bar  and  see  both  sides  of  the  disk.     On  the  front  of 


ENGINEERING   CHEMISTRY 


707 


7o8  DNGlNEiDRING    CHEMISTRY 

the  sight-box  a  hood  is  so  placed  as  partially  to  screen  the  eyes 
of  the  observer  from  the  lights. 

At  one  end  of  the  bar  is  the  light  to  be  tested.  This  is  con- 
nected to  a  pipe  sealed  in  mercury,  so  that  it  may  be  moved  back 
and  forth  or  raised  and  lowered  at  pleasure.  It  is  usually  ar- 
ranged with  a  micrometer  cock  so  that  the  rate  of  flow  may  be 
regulated  as  closely  as  may  be  necessary. 

At  the  other  end  of  the  bar  is  a  candle  balance.  The  balance 
is  usually  arranged  for  two  candles  and  all  readings  are  multiplied 
by  2.  This  balance  is  so  constructed  that  the  position  of  the 
candles  may  be  adjusted  vertically  or  horizontally. 

This  end  bar  is  so  arranged  that  the  candle  balance  may 
be  removed  and  a  standard  burner  put  in  its  place.  The  standard 
burner  commonly  used  is  a  Sugg  Argand  burner,  size  D.  This 
is  covered  with  a  thin  sheet  metal  chimney,  ij4,  inches  diameter. 
This  chimney  has  an  opening  on  one  side,  ^^/go  inch  high  and  i}^ 
inches  wide.  On  the  opposite  side  the  chimney  is  cut  away  to 
prevent  light  being  reflected  through  the  slot  in  front.  Th^  stand- 
ard burner,  like  the  one  through  which  the  gas  is  tested,  is  so 
arranged  that  it  may  be  adjusted  in  all  directions. 

A  meter  to  measure  the  gas  is  necessary.  As  gas  is  burned  at 
the  rate  of  5  feet  an  hour  when  being  tested,  the  meter  is  so 
geared  that  one  of  the  hands  makes  a  complete  revolution  each 
time  a  twelfth  of  a  foot  of  gas  passes.  A  clock  is  attached  to 
the  meter  with  a  large  second,  hand,  so  when  the  meter  hand 
mentioned  and  the  second  hand  move  together,  gas  is  passing  at 
the  rate  of  5  feet  an  hour.  In  addition  to  these  hands  are  one 
indicating  feet  and  one  minutes.  Some  meters  are  furnished  with 
a  third  set  of  hands  reading  feet  and  hundreds. 

The  meter  has  a  thermometer  to  show  the  temperature  of  the 
gas  and  a  universal  level  so  that  it  may  be  properly  leveled.  On 
the  side  is  a  glass  gauge  and  a  mark  indicating  the  height  of  the 
water,  which  should  always  be  constant.  The  pipe  connections 
to  the  meter  are  so  arranged  that  opening  a  cock  will  allow  the 
gas  to  pass  around  instead  of  through  it.  This  permits  the  op- 
erator to  start  or  stop  the  meter  at  pleasure  without  interfering 
with  the  light. 


e:ngine:kring  chemistry  709 

A  pressure  gauge  connected  with  the  various  parts  of  the  ap- 
paratus enables  the  operator  to  ascertain  the  pressure  of  the  gas 
at  different  points.  One  of  these  connections  is  to  the  pipe  a 
short  distance  below  the  test  burner.  This  gives  the  pressure 
near  the  point  of  ignition.  The  pressure  is  read  in  inches  and 
fractions  of  an  inch  of  water. 

A  gas  governor  is  connected  before  the  inlet  to  the  meter, 
which  reduces  the  pressure  to  about  i^  inches  of  water.  Beyond 
the  meter  is  a  smaller  governor  which  reduces  the  pressure  to 
about  0.9  of  an  inch  and  prevents  alteration  of  the  flow  of  gas 
due  to  the  irregularities  in  the  meter. 

Black  screens  are  arranged  to  screen  the  eye  of  the  observer 
from  the  light.  These  are  sometimes  fixed  and  at  others  set  on 
the  bar.  The  latter  arrangement  is  preferable,  as  they  may  be 
moved  to  suit  different  positions  of  the  sight-box. 

For  testing  gas  of  not  over  18  candle-power  the  Standard  I^on- 
don  Argand  burner  is  used.  For  higher  candle-power  gas  the 
ordinary  sawed  lava  tip  is  best.  The  latter  is  commonly  known 
as  the  batwing  burner. 

The  photometer  should  be  set  up  in  a  small,  light-proof  room 
with  dead  black  walls.  The  latter  can  be  hung  with  black  vel- 
vet or  painted  with  glue  and  lampblack.  Great  care  should  be 
taken  to  insure  proper  ventilation  without  draft.  The  tempera- 
ture of  the  room  should  be  kept  as  near  60°  F.  as  possible,  and 
the  air  should  not  be  allowed  to  become  vitiated  by  the  products 
of  combustion.  The  table  should  be  set  so  that  readings  may  be 
taken  from  both  sides  of  the  bar. 

Manner  of  Using  the  Photometer. 

When  one  starts  to  use  a  new  photometer,  or  one  with  which 
the  experimenter  has  not  previously  worked,  the  instrument 
should  be  carefully  verified. 

First  make  sure  that  the  lines  defining  the  distance  between 
the  lights  are  the  proper  distance  apart  and  parallel,  and  that  the 
bar  is  perpendicular  to  and  midway  between  them.  Next"  see 
that  the  bar  is  level.  The  disk  must  be  at  right  angles  to  the  bar, 
and  the  small  pointer  under  the  sight-box  in  line  with  the  disk. 


7IO  e:n GIN  BERING    CHEMISTRY 

The  two  mirrors  should  be  made  of  the  best  plate  glass  and  well 
silvered.  They  should  be  kept  clean.  The  disk  should  exactly 
bisect  the  angle  made  by  the  mirrors.  The  bar  should  be  veri- 
fied so  that  the  operator  may  be  sure  that  it  is  properly  divided, 
and  the  meter  should  be  tested  with  a  meter  prover.  In  test- 
ing the  meter  be  sure  that  the  temperature  of  the  room,  of  the 
water  in  the  meter,  and  of  the  water  in  the  prover  are  the  same. 
The  pressure  gauge  should  be  verified  by  a  U-shaped  water  gauge. 
The  knife  edges  of  the  candle  balance  should  be  clean  and  sharp, 
and  the  lever  should  be  free  to  move  without  rubbing.  The 
weight  for  the  candle  balance  should  be  weighed  on  an  analytical 
balance  to  be  sure  that  it  is  correct. 

For  testing  coal  gas  no  choice  is  allowed  in  the  burner,  but 
when  water  gas  or  any  high  grade  gas  is  to  be  tested  it  is  neces- 
sary to  get  a  burner  suited  to  the  gas.  The  most  suitable  burner 
can  be  quickly  determined  by  experiment,  and  the  greatest  efifi- 
ciency  is  usually  obtained  with  a  burner  of  such  size  that  the  gas 
is  almost  on  the  point  of  smoking.  When  the  photometer  light  is 
burned  continually,  as  is  usually  the  case  in  gas  works,  the  tip  on 
the  fiat-flame  burner  should  be  changed  at  intervals  of  two  or 
three  weeks.  Care  should  be  taken  that  the  tip  is  smooth.  Any 
tips  that  are  chipped  on  top  or  rough  in  the  slot  should  not  be 
used. 

In  preparing  for  a  test,  the  burner  and  candles  should  be  placed 
in  their  proper  positions  and  at  such  a  height  that  the  center  of 
the  flames  will  be  on  a  level  with  the  center  of  the  disk.  The  height 
of  the  candle  flame  is  taken  when  the  candle  end  of  the  balance 
is  down.  The  gas  should  be  burned  long  enough  to  be  sure  that 
the  apparatus  is  cleaned  out  and  that  fresh  gas  is  being  burned. 
Before  starting  it  is  necessary  to  control  the  pressure  under  the 
burner  so  that  it  will  not  vary  during  the  test.  The  governor  on 
the  outlet  of  the  meter  will  do  this  if  it  is  in  order.  If  the  pres- 
sure varies,  the  governor  must  be  cleaned  before  starting  the  test. 
During  the  test  the  pressure  gauge  must  be  shut  off,  as  in  case 
there  is  change  of  pressure  it  will  store  or  give  out  enough  gas 
to  vitiate  the  result.  The  meter  should  be  level  and  the  water  at 
the  proper  height. 


EINGINKERING    CHEMISTRY  7II 

The  wicks  of  the  candles  should  never  be  touched.  The 
candles  are  lighted  and  allowed  to  burn  until  the  wick  curls  over 
to  the  edge  of  the  flame  and  burns  away  as  the  candle  is  con- 
sumed. The  end  of  the  wick  should  glow.  No  test  should  be 
started  until  th^  wicks  are  bent  over  and  the  ends  are  glowing. 
The  candles  should  always  be  burned  eight  or  ten  minutes  before 
starting  a  test.  A  common  practice  which  gives  good  results  is 
to  allow  the  candles  to  burn  eight  or  ten  minutes  and  then  extin- 
guish them  for  two  or  three  minutes.  The  candles  are  then  re- 
lighted and  allowed  to  burn  about  two  minutes  before  starting 
the  test.  They  are  commonly  placed  in  the  holders  in  such  a  way 
that  the  ends  of  the  wicks  are  as  far  away  from  each  other  as 
possible. 

When  the  apparatus  has  been  brought  to  the  proper  condition 
for  testing  the  flow  of  gas  is  adjusted  to  as  near  5  feet  an  hour 
as  possible,  and  the  meter  is  allowed  to  run  until  the  twelfth-of- 
a-foot  hand  points  to  o,  when  it  is  by-passed.  The  clock  is  stopped 
at  o.  The  candles  are  counterbalanced  by  the  sliding  weight  on 
the  balance  lever  until  the  weight  almost  carries  the  lever  down. 
In  a  few  seconds  the  candles  burn  sufficiently  to  allow  the  bal- 
ance to  fall,  and  at  that  instant  the  meter  and  clock  should  be 
started.  As  soon  after  as  possible  the  40-grain  weight  should  be 
dropped  into  the  scale  pan,  which  brings  the  candles  down  again. 
The  operator  should  always  move  about  the  room  deliberately  so 
as  to  avoid  as  far  as  possible  creating  currents  of  air.  The 
candle  flames  must  be  still  before  beginning  to  take  readings. 

A  reading  should  be  taken  every  minute  for  ten  minutes. 
When  the  screen  is  apparently  illuminated  equally  on  both  sides 
it  should  be  moved  a  little  to  the  right  and  to  the  left,  and  in 
each  case  the  illumination  on  that  side  should  increase.  Five 
readings  should  be  taken  on  one  side  of  the  bar  and  the  sight- 
box  turned  around  and  five  taken  from  the  opposite  side.  In 
case  the  bar  is  accessible  from  only  one  side,  the  readings  should 
be  made  with  one  eye  and  the  screen  turned  in  the  sight-box 
after  half  have  been  completed.  This  will  eliminate  the  errors 
due  to  possible  dift"erences  in  eyes  and  in  the  sides  of  the  screen. 

The  last  reading  should  be  taken  during  the  first  half  of  the 


712  DNGINEEJRING   CHEMISTRY 

tenth  minute  and  the  times  noted  when  the  candle  balance  falls, 
and  when  the  gas  hand  completes  its  tenth  revolution.  The  tem- 
perature of  the  gas  and  the  reading  of  the  barometer  should  also 
be  noted.  After  this  the  candles  may  be  extinguished.  They 
should  be  blown  out  and  the  ends  of  the  wicks  extinguished  with 
a  piece  of  sperm.  The  wicks  should  never  be  touched  with  any- 
thing else. 

If  the  candle  balance  falls  in  less  than  nine  and  one-half  or 
more  than  ten  and  one-half  minutes,  or,  if  the  gas  hand  takes 
less  than  nine  and  one-half  or  more  than  ten  and  one-half  min- 
utes to  make  lo  revolutions,  the  test  should  be  discarded.  Long 
practice  has  shown  that  withiji  these  limits  the  light  given  by  the 
candles  vary  approximately  with  the  consumption  of  sperm  and 
that  given  by  the  burner  approximately  with  the  gas  consumed. 

If  the  candles  take  x  seconds  to  burn  40  grains  and  the  gas 
hand  y  seconds  to  make   10  revolutions,  the    average    reading 

V  600  V  • 

multiplied  by  2  should  be  multiplied  by    -f —   X  or  - — 

600  X  X 

This  will  give  the  candle-power  of  the  gas  uncorrected  for 
temperature  and  pressure. 

The  standard  pressure  is  30  inches  of  mercury,  and  the  stand- 
ard temperature  is  60°  F.  To  correct  the  pressure  multiply  by 
30  and  divide  by  the  barometric  reading.  In  correcting  for  tem- 
perature the  gas  is  assumed  to  be  a  perfect  gas  saturated  with 
water-vapor.  The  following  is  the  formula  for  correction  for 
pressure  and  temperature : 
17.64  (/;  —  «)     1 


71   =■ 


460 


1  Numerous  inquiries  having  been  received  for  the  derivation  of  this  formula,  it  is 
given  as  follows  : 

A  gas  expands  or  contracts  1/490  of  its  volume  at  32°  F.  per  a  change  of  1°  F. 
492  —  32  =  460  =  temp,  of  32°  F.  on  absolute  scale. 
460  +  60  =  520  =  temp,  of  60°  F.  on  absolute  scale. 
The  volumes  of  a  given  quantity  of  gas  are  to  each  other  as  the  distances  from  the 
absolute  zero. 

If  60°  F.  =  520°  absolute  is  taken  as  the  standard  temp.,  the  correclion  for  a  dry  gas 
for  temp,  is  : 

V  X  ^^  ft.     [v  =  vol.  at  temp.  P  F.  =  (460  +  P)  abs] 
460 

{Continued  on  page  ■/ 1  J  ) 


e:nginekring  chemistry  713 

n  ^  the  number  by  which  the  observed  volume  is  to  be  multi- 
pHed  to  reduce  it  to  30  inches  and  60°  F. ; 

h  =  the  height  of  the  barometer  in  inches ; 

t  =^  the  temperature  Fahrenheit; 

a  =  the  tension  of  aqueous  vapor  at  ^°. 

The  table  on  page  714  will  facilitate  corrections  for  various 
pressures  and  temperatures. 

Inasmuch  as  a  flame  is  not  perfectly  transparent,  a  test  made 
with  it  at  right  angles  to  the  bar  does  not  give  the  mean  of  the 
light  that  is  emitted  horizontally.  The  richer  the  gas  the  greater 
is  the  difference  between  the  candle-power  measured  on  the  flat 
and  on  the  edge  of  the  flame.  A  gas  that  gives  25  candles  meas- 
urement flat  will  not  give  over  19.5  candles  measured  on  the 
edge.  When  the  flame  is  at  ah  angle  of  10°  with  the  bar  it  gives 
almost  as  much  light  as  when  it  is  measured  at  90°  F. 

The  best  photometers  are  made  so  that  the  burner  may  be 
turned  on  its  axis  and  the  light  measured  at  all  angles. 

When  it  is  desired  to  measure  the  light  emitted  by  a  burner  at 
various  altitudes,  mirrors  are  used  to  reflect  the  light  to  the  disk, 
as  the  latter  is  kept  vertical  and  in  the  same  horizontal  plane  as 
the  standard  burner.  In  such  cases  it  is  necessary  to  test  very 
carefully  the  amount  of  light  absorbed  by  the  mirroi:s  at  all 
angles. 

There  is  a  popular  impression  that  photometrical  work  is  not 
accurate  and  therefore  not  to  be  depended  upon,  but,  if  care  is 
taken  by  the  operator  in  his  work,  and  all  the  apparatus  is  prop- 
erly adjusted,  the  error  will  be  less  than  i  per  cent.  By  taking 
the  average  of  a  series  of  measurements  the  error  can  be  reduced 
to  a  point  where  it  is  inappreciable. 

{ Conini  ued  from  page  ji2. ) 
If  30"  is  taken  as  the  standard  pressure,  the  pressure  correction  for  a  dry  gas  is  z/  +    '  . 
The  correction  for  temp,  and  pressure  of  a  dry  gas  is 

5-       X  4-  =17/3        '' 


460  4-  /     '     30  460  -t-  / 

The  pressure  in  the  meter  which  balances  that  of  the  atmosphere  (A)  is  due  in  small 
part  to  the  water  vapor  (a).  That  due  to  the  gas  is  {h  —  a).  At  the  standard  pressure  and 
temp,     h  =  30",  a  =  0.5179",  {h  —  a)  =  30  —  0.5179  =  29.4821.    In  order  to  make  the  factor 

^iVi  i—^ -)  reduce  to  I  (one)  at  the  standard  conditions  when  ^(30)  is  reduced  to  20.4821 

>    400  +  t  '  ^  ^ 

to  constant,  i-/]A,  must  be  raised  to  17.64. 


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ENGINEERING    CHEMISTRY 


715 


7i6 


ENGINEERING    CHEMISTRY 


Fig-    143- 


ENGINEERING    CHEMISTRY 


/  V 


The  Standard  Bar  Photometer  as  designed  by  the  U.  G.  I.  Co., 
after  years  of  special  study  in  the  field  of  gas  photometry  is 
shown  in  Fig.  142. 


Fig.  144- 


The  standard  used  for  light  is  the  lo-candle-power  Harcourt 
pentone  lamp.    Fig.  143. 


7i8  Enginee:ring  chemistry 

Candle-power  Computer — Copyrighted  (Fig.  144). 

The  computer  is  a  circular  card  slide  rule,  and  was  designed 
by  the  Engineers  of  the  United  Gas  Improvement  Co.,  to  enable 
the  observer  to  determine  the  candle-power  of  a  gas  direct  from 
the  readings  taken  on  a  bar  photometer  without  having  to  resort 
to  the  usual  mathmetical  calculations. 

This  computer  is  intended  for  use  with  a  lo-candle  power 
standard,  but  may  be  adapted  to  use  with  other  standards.  Com- 
puters are  also  made  having  a  range  over  the  value  of  standards 
from  4  to  8  candles. 


PYROMETRY. 


Revised  by  Thomas  B.  Stillman,  Jr.,  M.  E. 

Pyrometry,  or  the  art  of  measuring  high  temperatures,  has  re- 
ceived, in  the  past  few  years,  considerable  attention  from  engi- 
neers and  metallurgists. 

This  is  especially  so  in  the  direction  of  metallurgical  engineer- 
ing, where  more  uniform  methods  of  heating  and  controlling 
heat  have  developed.  In  many  processes  of  melting,  refining, 
tempering,  etc.,  certain  temperatures  are  required,  from  which, 
should  much  variation  occur,  the  products  would  be  ruined. 

Many  form  of  pyrometers  have  been  invented,  but  only  a  very 
few  have  accomplished  their  purpose.  Many  are  admirable  in 
design  and  construction,  and  prove  accurate  and  trustworthy  in 
the  laboratory,  but  fail  utterly  when  applied  in  practice  at  high 
temperatures. 

The  standard  of  reference  for  all  temperatures  above  212°  F. 
is  the  air  thermometer  and  all  pyrometers  are  usually  standard- 
ized by  comparison  with  it.  However,  for  practical  service  in 
engineering  and  metallurgical  lines,  the  air  thermometer  is  not 
well  adapted,  and  will,  accordingly,  not  be  given  further  consid- 
eration here. 

Some  of  the  instruments  which  have  proved  most  satisfactory 
in  actual  service  for  measuring  high  temperatures  may  be  briefly 
described  as  follows : 


DNGINKERING    CHEMISTRY 


719 


Electrical  Resistance  Type  of  Instrument. 

Of  the  electrical  resistance  types  of  instruments,  the  Heraeus 
Quartz  Glass  Thermometer  is  an  excellent  example.  These  may 
be  made  to  cover  a  temperature  range  from  — 330°  F.  to  -\~  1,300° 
F.,  their  resistance  being  adjusted  to  give  an  accuracy  w^ithin 
0.2°  F.  By  equipping  the  indicator  with  two  or  more  scales, 
each  one  of  them  covering  a  different  temperature  range,  extreme 
accuracy  may  be  obtained  in  reading  the  instrument  over  very 
wide  temperature  limits. 

The  principle  of  operation  is  based  upon  the  varying  resistance 
of  a  platinum  spiral  with  change  in  temperature,  this  change  in 
resistance  being  measured  by  an  application  of  the  Wheatstone 
Bridge  Principle  in  which  the  galvanometer  is  graduated,  not  in 
terms  of  electrical  resistance,  but  directly  in  temperature  degrees. 


Fig.  145.— 5,  Battery;  G,  Galvanometer;  Th,  Thermometer;  A,  Sliding  Resistance; 
P,  Test  Resistance;  Sch,  Switch. 

By  referring  to  Fig.  145,  it  will  be  readily  seen  that  when  the 
arms  i  and  2  are  equal  in  resistance,  and  when  3  and  4  are  equal, 
there  will  be  a  balanced  condition,  so  that  the  galvanometer  will 


720  engine:e:ring  che:mistry 

register  zero.  If  however,  the  resistance  of  the  platinum  spiral 
in  the  thermometer  is  different  from  the  resistance  arm  3  there 
will  be  an  unbalanced  condition  resulting  in  a  deflection  of  the 
galvanometer.  The  magnitude  of  the  deflection  is  dependent 
upon  the  difference  in  temperature  and  upon  the  applied  voltage 
of  the  battery.  In  order  that  the  voltage  shall  always  be  the 
same,  when  a  measurement  is  taken,  it  is  necessary  to  provide  a 
series  resistance  in  the  battery  circuit  to  compensate  for  the  drop 
in  potential  in  the  batteries  as  they  become  aged  or  discharged. 

In  order  to  check  this  constant  voltage  it  is  only  necessary  to 
connect  into  that  arm  of  the  bridge,  across  which  the  thermom- 
eter is  ordinarily  connected,  a  standard  resistance  equal  to  the 
resistance  of  the  thermometer  at  the  maximum  temperature  for 
which  the  galvanometer  is  calibrated.  Then  the  proper  voltage 
is  indicated  when  the  pointer  coincides  with  that  graduation. 

As  commercially  supplied  the  thermometers  are  made  up  of 
chemically  pure  platinum  spirally  wound  upon  a  tube  of  quartz 
glass.  A  larger  tube  of  the  same  material  is  then  placed  over  it, 
the  whole  fused  together,  thus  protecting  the  spiral  against  change 
in  resistance  from  any  cause  except  heat.  These  spirals,  her- 
metically sealed  in  quartz  glass,  are  then  mounted  in  outside 
casings  of  steel,  lead,  silica,  copper,  or  any  other  material,  and  are 
provided  with  terminal  heads  suitably  designed  for  attachment 
to  the  apparatus  in  which  they  are  to  be  inserted.  Any  number 
of  these  thermometers  may  be  connected  to  a  central  measuring- 
station  by  ordinary  well  insulated  copper  wires.  These  connect- 
ing wires  of  different  lengths  are  all  equalized  in  resistance  by  in- 
serting at  the  cental  station  little  series  resistances  to  make  up 
that  line  resistance  for  which  the  instrument  is  calibrated.  The 
very  small  line  resistance  fluctation  due  to  temperature  change, 
rarely  over  one-tenth  of  an  ohm,  is  so  very  small  compared  with 
the  resistance  of  the  platinum  thermometer  wires  (50  ohms  at 
32°  F.)  that  the  error  resulting  therefrom  is  of  no  consequence. 

A  central  measuring  station  is  made  up  in  switchboard  or 
portable  form  with  switches  to  accommodate  the  number  of 
thermometers  which  will  be  used  with  it.  There  is  also  a  switch 
for  connecting  the  standard  resistance  for  voltage  adjustment  and 


ENGINKE^RING    CHEMISTRY 


721 


an  adjustible  resistance  is  provided  for  controlling  this  voltage. 
The  galvanometer  can  be  either  a  simple  indicator  or  a  graphic 
recorder,  as  desired.  Fig.  146  shows  a  portable  form  of  this  in- 
strument which  may  be  conveniently  carried  and  set  up  for  use 
anywhere. 


Fig.   1^6. 


This  is  especially  valuable  in  test  work,  as  for  example,  in 
boiler  testing,  where  one  man  can  sit  at  a  table  and  by  pressing 
suitable  buttons,  take  every  temperature  necessary  in  connection 
with  the  test,    and  with  a  degree  of  accuracy    that    cannot  be 

46 


722  ENGINEERING    CHEMISTRY 

equalled  by  the  use  of  mercury  thermometers.  The  fact  that  the 
temperatures  are  correct  as  read  is  an  especially  desirable  feature, 
eliminating,  as  it  does,  the  necessity  for  making  "cold  end"  cor- 
rections required  in  the  use  of  thermo-couple  pyrometers. 

The  practical  application  of  these  electrical  resistance  instru- 
ments, both  in  the  stationary  and  portable  types,  covers  a  wide 
field,  from  the  lowest  temperatures  in  liquid  air,  up  through 
refrigeration,  heating  and  ventilation,  drying  and  enamelling 
kilns,  boiler  operation,  chemical  manufacture,  steel  treatment, 
etc.,  and  for  the  temperature  range  which  they  are  designed  to 
cover  they  cannot  be  equalled  for  unvarying  accuracy  over  long 
periods  of  time,  strict  interchangeability  of  parts  and  convenience 
in  operation. 

Thermo-Electric  Pyrometers. 

The  Le  Chatelier  electrical  pyrometer  is  an  excellent  instru- 
ment for  use  where  very  accurate  measurements  are  required  in 
high  temperature  work.  With  this  pyrometer,  temperatures  be- 
tween o°  and  1, 600°  C.  or  0°  to  3,000°  on  the  Fahrenheit  scale 
can  be  satisfactorily  measured. 

The  instrument  consists  of  a  galvanometer  of  an  approved 
type,  a  platinum,  platinum  iridium,  or  platinum  rhodium  thermo- 
couple or  element,  protected  in  a  suitable  manner,  and  the  wires 
which  connect  the  thermo-couple  to  the  galvanometer.  A  junc- 
tion of  the  platinum  and  platinum  allo}^  wire  is  formed,  and  on 
insertion  of  this  junction  into  the  heat,  a  slight  electrical  current 
is  generated.  This  current  is  carried  by  the  insulated  wires  to 
the  galvanometer,  which  is  graduated  to  read  in  millivolts  and  in 
degrees  Fahrenheit  or  Centigrade. 

Fig.  147  shows  a  portable  form  of  the  LeChatelier  electric 
pyrometer.  With  this  type  of  instrument  it  is  only  necessary  to 
set  the  galvanometer  in  a  convenient  protected  place  on  a  firm 
base,  insert  the  thermo-couple  a  few  inches  into  the  furnace,  and 
after  connecting  the  binding  posts  on  the  galvanometer  to  those 
on  the  thermo-couple  by  insulated  wires,  the  instrument  is  ready 
for  use. 

W^hen  desirable,  any  number  of  thermo-couples  can  be  con- 


e:ngine;e;ring  chemistry 


723 


I 


nected  to  the  same  galvanometer  by  means  of  a  switchboard,  and 
in  this  manner  the  temperature  of  several  furnaces  or  metal  baths 
can  be  determined  by  turning  a  switch.  The  galvanometer  can  be 
placed  300  feet  from  the  thermo-couple  inserted  in  the  heat  and 
the  temperature  obtained  just  as  accurately  as  when  the  galvan- 
ometer is  close  to  the  thermo-couple. 


Fig.  147. 

Due  to  the  expense  of  the  platinum,  platinum-rhodium  couples 
of  the  LeChatelier  pyrometers,  a  number  of  ''base  metal"  pyrom- 
eters have  been  devised,  of  which  the  William  H.  Bristol  Low 
Resistance  Indicating  and  Recording  Electric  Pyrometer,  is  a 
very  good  example.  In  this  case  the  thermo-couple  consists  of 
two  special  alloys.  The  electro  motive  force  secured  with  the 
special  alloys  of  these  pyrometers  is  about  five  times  as  great  as 
that  secured  with  the  standard  platinum,  platinum-rhodium 
couples.  It  is  therefore  possible  to  use  more  rugged  instruments. 
The  platinum,  platinum-rhodium  couples,  require  jeweled  instru- 
ments to  secure  very  accurate  results. 

For  average  industrial  conditions  the  "base  metal"  type  of 
instrument  will  meet  all  requirements  in  a  most  satisfactory  way. 


724 


KNGINEJERING   CHEMISTRY 


The  temperaure  range  is  not  as  great,  however,  as  the  platinum, 
platinum-rhodium  couples,  and  due  to  crystallization  of  the  alloys, 
with  consequent  change  in  the  electric  motive  force  generated,  it 
is  not  satisfactory  to  use  them  continuously  at  temperatures  above 
2,000°  F.  Fig.  148  illustrates  a  combination  indicating,  and  re- 
cording unit  of  the  William  H.  Bristol  electric  pyrometers  as  they 
are  supplied  for  commercial  installation. 


Fig.  148.— Illustration  of  combination  indicating  and  recording  unit  of 
Wm.  H.  Bristol  electric  pyrometers. 


Due  to  the  large  diameter  of  the  ''base  metal"  couples  compared 
to  that  of  the  platinum,  platinum-rhodium  couples,  and  to  the 
possibilities  of  impurities  being  present  in  the  alloys  of  the  "base 
metal"  couples,  the  accuracy  of  this  type  is  inferior  to  the  plati- 
num-rhodium couples.  This  is  partly  due  to  the  presence  of 
"parasite  currents"  which  are  frequently  set  up  in  the  base  metal 
couples,  these  "parasite  currents" — even  though  slight — being 
sufficient  to  cause  considerable  temperature  deviations  on  the 
graduated  scale.  Accordingly,  where  Ytry  accurate  work  is  re- 
quired, or  where  constant  temperatures  above  2,000°  F.  are  to 
be  measured,  the  platinum,  platinum-rhodium  couples  should  al- 
ways be  used. 

As  the  thermo-couple  type  of  instrument  indicates  the  differ- 
ence in  temperature  between  the  hot  and  cold  end  of  the  couple. 
it  is  essential  that  the  temperature  of  the  cold  end  be  obtained 
with  a  mercury  thermometer  hanging  near  it,  in  order  that  the 
necessary   corrections   may   be   made   to   the   readings   obtained. 


ENGINEERING   CHEMISTRY 


725 


Thus,  if  the  instrument  is  standard  at  70°  F.,  and  the  temperature 
of  the  cold  end  of  the  thermo-couple  is  100°,  to  obtain  the  correct 
reading  of  the  hot  end,  30°  should  be  added  to  the  reading  indi- 
cated on  the  graduated  scale.  In  a  similar  way,  if  the  cold  end  of 
the  thermo-couple  is  less  than  70°  F.,  the  difference  between  the 
two  temperatures  should  be  subtracted  from  the  reading  indicated 
on  the  graduated  scale. 

Optical  and  Radiation  Pyrometers. 

In  the  measurement  of  very  high  temperatures,  especially  those 
above  3,000°  F.  (the  upper  limit  of  the  platinum,  platinum-rho- 
dium couple  type  of  pyrometer)  some  type  of  optical  or  radiation 
pyrometer  is  necessary. 


Fig.  149.— Fery  radiation  pyrometer.     Ready  for  use. 

Of  these  the  Radiation  Pyrometer  is  the  more  practical  form 
and  one  of  the  best  instriuiients  of  this  type  is  the  pyrometer 
invented  by  M.  Fery,  Professor  of  Physics  at  the  Ecole  dePhysics 


726  Engine;e:ring  chemistry 

et  de  Chimie.  The  radiation,  which  emanates  from  a  hot  body, 
or  which  passes  out  through  an  observation  hole  in  the  wall  of  a 
furnace,  falls  upon  a  concave  mirror  and  is  thus  brought  to  a 
focus.  In  this  focus  is  a  thermo-electric  couple,  whose  tempera- 
ture is  raised  by  the  radiation  falling  upon  it;  the  hotter  the 
furnace,  the  greater  the  rise  of  temperature  of  the  couple. 

Since  the  energy  radiated  from  a  hot  body  increases  very 
rapidly  as  the  temperature  is  raised,  it  follows  that  the  Fery 
pyrometer  is  far  more  sensitive  at  high  than  at  low  temperatures. 
Temperatures  as  low  as  i,icx)°  F.  can  be  read,  but  the  instrument 
is  more  suitable  for  high  temperature  work.  As  examples  of 
high  temperature  measurements  made  with  the  Fery  pyrometer 
we  may  mention  the  temperature  of  the  sun  14,072°  F.,  deter- 
mined by  Professor  Fery,  as  well  as  the  temperature  of  the  iron 
in  a  thermic  mold,  which  was  found  to  be  4,532°  F. 

Seger  Cones. 

Another  system  of  high  temperature  measurement  largely  used 
in  practical  manufacturing  processes  is  the  melting  of  Seger 
cones.  This  method  is  but  approximate  and  by  the  use  of  it  only 
the  highest  temperature  attained  is  recorded,  it  being  impossible 
to  note  any  fluctations  in  temperature  which  may  take  place. 

The  manufacture  of  Seger  cones  in  the  United  States  has  been 
undertaken  by  Professor  Orton  who  followed  closely  the  lines  of 
the  original  series  developed  by  Professor  Seger  in  Germany,  and 
further  improved  by  the  Imperial  Physical  Testing  Station  at 
Berlin.  These  cones  have  been  numbered  from  0.022  to  36,  and 
cover  a  temperature  range  from  1,004  to  3,362°  F.  A  Seger  cone 
is  regarded  as  having  melted  when  its  tip  has  kent  over  and 
touched  the  plane  of  the  base  on  which  the  cone  rests. 

Unfortunately,  Seger  cones  do  not  accurately  measure  temper- 
atures, their  melting  points  depending  not  only  on  the  tempera- 
ture of  the  fire  but  also  upon  the  duration  of  the  time  they  are 
exposed  to  the  heat  and  the  kind  of  furnace  in  which  they  are 
used.  Also,  if  a  cone  has  been  used  once,  it  cannot  be  used  again 
even  though  it  shows  no  signs  of  having  melted,  as  its  indications 


e;ngine:e:ring  che;mistry  727 

upon  being  used  a  second  time  are  at  considerable  variance  with 
a  new  cone  of  the  same  number. 

The  true  value  of  the  pyrometric  cone  system  is  not  the  exact 
measurement  of  temperatures,  but  is  the  fact  that  it  does  some- 
thing which  no  mere  measurement  of  temperature  by  itself  or 
no  measurement  of  time  and  temperature  together  can  do.  The 
vitrification  of  a  piece  of  clay-ware  and  the  melting  of  a  cone  are 
strictly  comparative  processes,  and  the  factors  which  control  one 
are  the  same  as  control  the  other.  For  that  reason  they  have  a 
very  extensive  and  satisfactory  use  in  the  clay-working  industries. 


APPENDIX. 


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O  !/)  ?  rt 


U5     '     1;    U 

4,  ""  bccc 


«     a  a  ^  ^-  J'       hf 


«^  (3   (U   3-« 

°3^^n 


'^s::;a^ 
^ll_a_ 


•-0    fJ    1/3    "4  *-•  ■»-' 

§Brtrtoi«e^- 
2  "^X     -c  ^  3  (U 

P  g  ^.  ri  eg  ci'O 


j;i;        0< 


lU  II 


i  ^,  lU  <U  ^  ^.TT  ";  ^ 
tf  .ti  5!  ^  °  3  C 

;zOo^bc2 


•  (A  ^  v> 

•-  i  ^'      * 


•"  d  ^-  '^'^  a   - 

•^•ria.;:^  c  <fl  o 


rt  p,(uo  "5  p.'^^b 


bca 


301" 


3  4;  ^  Zoi.'''^a  i: 


a  rt 


b  '^  o  bc-S 


^Oh 


732 


DNGINEERING   CHEMISTRY 


1.  Camphor  is  sometimes  used  in  mixture  with  "explosive  gelatine",  we  have  not 
found  it  in  any  samples  of  gelatine  dynamite.  If  present,  it  would  be  dissolved  by  the 
ether-alcohol  solution  and  would  be  saponified  with  the  resin.  It  can  be  separated  from 
the  resin  as  follows:  Upon  the  addition  of  hydrochloric  acid  (in  foregoing  scheme)  for 
the  separation  of  the  resin,  the  camphor  will  also  separate,  and  after  filtering  can  be 
transferred  to  a  weighed  porcelain  evaporating  dish  and  their  sum  weight  determined. 
Heat  is  then  applied  carefully  and  the  camphor  gradually  vaporized  leaving  the  resin. 
The  latter  is  then  weighed;  the  difference  in  the  two  weights  giving  the  amount  of 
camphor. 

2.  The  method  of  recognition  for  the  nitro  glycerine  would  be  as  follows:  A  sample 
of  the  nitro-gelatiue  is  extracted  with  alcohol-ether  and  the  soluble  gun  cotton  is  separated 
by  means  of  chloroform,  and  the  ether-alcohol  and  chloroform  eliminated  by  evapora- 
tion, the  nitrates  (if  present)  removed  from  the  oily  liquid,  in  the  manner  indicated  in 
the  foregoing  scheme  and  a  portion  of  the  nitro-glycerine  tested  with  ferrous  sulphate 
for  the  nitrogen  oxide  reaction;  another  portion  is  tested  with  iodide  of  potassium,  starch 
hydrochloric  acid  and  zinc,  when  the  solution  assumes  a  deep  blue  color  characteristic 
of  nitro-glycerine.  The  small  amounts  of  paraffine  and  resin  present  do  not  interfere 
with  these  tests.  Another  portion  of  the  oily  liquid  of  sufficient  amount  is  subjected  to 
the  usual  ballistic  test,  or  its  explosive  property  can  be  shown  by  placing  a  drop  of  the 
liquid  upon  a  steel  anvil  and  producing  explosion  by  blow  of  a  hammer  upon  it. 


TABLES. 

Melting,  Boiling-Point,  Specific  Gravity  and  Specific  Heat  of  the  Elements, 
with  International  Atomic  Weights. 


Elements. 

Atomic 
weight 

Melting- 
point,  °C. 

Boiling- 
point,  °C. 

Specific  gravity 

Specific 
heat 

Aluminum 

Al 

27.1 

657 

I 470- I 700 

2.58 

0.2210 

Antimony 

Sb 

120.2 

630 

1500-1700 

6.62 

0.0495 

Argon 

A 

39.9 

-187.9 

—186. 1 

19.96  (H=i) 

0.1233 

Arsenic 

As 

75-0 

•185 

449-5 

5.70 

0.0824 

Barium 

Ba 

137.4 

850 

95' 

3.78 

0.0471 

Bismuth 

Bi 

208.5 

269 

1485 

9-74 

0.0305 

Boron 

B 

II. 0 

2250 

350^ 

2.53 

0.3060 

Bromine 

Br 

79.96 

-7.3 

59.00 

3.18 

0.1043 

Cadmium 

Cd 

112. 4 

321.7 

778 

8.64 

0.0547 

Caesium 

Cs 

132.9 

26.37 

670 

2.36 

0.0481 

Calcium 

Ca 

40.1 

780.81 

r.58 

0.1804 

Carbon 

C 

12,00 

3500 

3500 

I-75-3-55 

0.2410 

Cerium 

Ce 

140.25 

623 

7.04 

0.0447 

Chlorine 

CI 

35.45 

—  102 

-33-6 

2.49  (air=^i) 

0.1241 

Chromium 

Cr 

52.1 

1515 

6.92 

0.1039 

Cobalt 

Co 

59.0 

1530 

8.71 

0. 1030 

Columbium 

Cb 

94 

1950 

7.06 

.... 

Copper. 

Cu 

63.6 

1065 

2100 

8.95 

0.0933 

Erbium 

Er 

166 

.... 

4.77 

.... 

Fluorine 

F 

19 

-223 

-187 

1. 31  (air=i) 

0.2600 

Gadolinium 

Gd 

156 

1.31  {air=i) 



Gallium 

Ga 

70 

30.J5 

5.95 

0.0790 

Germanium 

Ge 

72.5 

900 

1350 

5.46 

0.0737 

Glucinum 

Gl 

9.1 

>96o 

1.85 



Gold 

Au 

197.2 

1065 

^9-^o  . 

0.0314 

Helium 

He 

4 

>— 271.3 

-267 

1.98  (H  =  i) 



Hydrogen 

H 

1.008 

—256.5 

-252.5 

0.0694  (air=i) 

3.4000 

Indium 

In 

115 

155 

Red  heal 

7.12 

0.0336 

i        ENGINEERING    CHEMISTRY 


■33 


Melting-,  Boiling-Point,  Specific  Gravity  and  Specific  Heat  of  the  Elements 
with  International  Atomic  VJe\ghts—{Confijiued) 


I 


Elements. 

Atomic 
weight. 

Melting- 
point,  °C 

Boiling- 
point,  °C 

Specific  gravity 

Specific 
heat 

Iodine 

I 

126.97 

114. 2 

184.35 

4-94 

0.0541 

Iridium 

Ir 

193.0 

1950 

•• 

22.42 

0.0323 

Iron 

Fe 

55.9 

1804 

7.68 

O.I  138 

Krypton 

Kr 

81.8 

-169 

—  151-7 

2  81  (air=i) 

Lanthanum 

La 

138.9 

810 

6.15 

0.0448 

Lead 

Pb 

206.9 

327 

[400-1600 

11.34 

0.0310 

Lithium 

Li 

7.03 

186 

<i4oo 

0.59 

0.9408 

Magnesium 

?JS 

24.26 

632.6 

IIOO 

1.72 

0.2456 

Manganese 

Mn 

55-0 

1245 

7-42 

O.I  2  17 

Mercury 

?^ 

200.0 

-38.85 

357 

13-70 

0.0334 

Molybdenum 

Mo 

96.00 

8.80 

0.0659^ 

Neodymium 

Nd 

143  6 

840 

6.95 

0  0450 

Neon 

Ne 

20 

—243 

9.96  (H=i) 

Nickel 

Ni 

58.7 

1484 

8.80 

0.  IO9I 

Nitrogen 

N 

14  04 

—210.5 

-^96 

0.967  (air=i) 

0.2438 

Osmium 

Os 

191 

2500 

22.48 

O.O3II 

Oxygen 

0 

16.00 

>— 230 

—184 

1.105  (air==i) 

0.2175 

Palladium 

Pd 

106.5 

I541 

IT.80 

0.0582 

Phosphorus 

P 

31.0 

44.2 

290 

1-83 

0.1699 

Platinum 

Pt 

194.8 

1780 

21  48 

0.0324 

Potassium 

K 

39.15 

62.5 

757-5 

0.87 

0. 1660 

Praseodymium 

Pr 

140.5 

940 

6.47 

.     ... 

Radium 

Ra 

225 

• . . 

Rhodium 

Rh 

103.0 

2000 

12.10 

0.0580 

Rubidium 

Rb 

85.5 

38.5 

696 

1.52 

Ruthenium 

Ru 

I01.7 

>i95o 

8.60 

0.06  II 

Samarium 

Sm 

150-3 

7-78 

Scandium 

Sc 

44.1 

.... 

Selenium 

Se 

79.2 

170-180 

690 

4.26 

00953 

Silicon 

Si 

28.4 

1200 

3500 

2.49 

0.1730 

Silver 

Ag 

107.93 

955 

2050 

10.53 

0.0557 

Sodium 

Ma 

23-05 

97.6 

877-5 

0.97 

0.2734 

Strontium 

Sr 

87.6 

900 

burns 

2.54 

Sulphur 

S 

3206 

ii5-'i9 

444-6 

2.04 

0.1630 

Tantalum 

Ta 

18-. 

2250 

10.70 



Tellurium 

Te 

127.6 

446 

1390 

6.20 

0.0475 

Terbium 

TW 

160 

. . . 

. . . 



Thallium 

Tl 

204.1 

301.7 

1600-1800 

n  85 

0.0326 

Thorium 

Th 

232.5 

11.00 

0.0278 

Thulium 

Tm 

171 

.... 

Tin 

Sn 

119.0 

232 

1450- 1600 

7-29 

0  0559 

Titanium 

Ti 

48.1 

3000 

3  54 

O.I  135 

Tungsten 

W 

184 

1700 

18.77 

0.0356 

Uranium 

U 

238.5 

800 

18.68 

0.0270 

Vanadium 

V 

51.2 

1680 

5.87 

O.II53 

Xenon 

Xe 

128 

—  140 

— 109. T 

4.42  (air^i) 

Ytterbium 

Yb 

1730 

Yttrium 

Yt 

89.0 



... 

3-80 

Zinc 

Zn 

654 

419 

91S 

7  H 

0.0935 

Zirconium 

Zt 

90.6 

1500 

4.15 

0.0660 

734 


Engine:e;ring  chemistry 
Conversion  Tables 


Found 

vSought. 

Factor. 

Found. 

Sought. 

Factor. 

AI2O3 

A\, 

0.53398 

Mg2P20, 

2Mg 

0.21883 

NH.Cl 

NH3 

0.31882 

MiijOa 

2Mn 

0.69695 

PtCle(NH,)2 

2NH3 

0.07692 

MngO, 

3Mn 

0.72084 

PtCle(NH,)2 

N, 

0.06329 

MnS 

Mn 

O.63211 

Pt 

2NH3 

O.17518 

Hg 

HgO 

1.07984 

(NHJ^SO, 

2NH3 

0.25815 

HgS 

Hg 

0.86208 

Sb,03 

Sb., 

0.83366 

MoS 

Mo 

0.49992 

Sb^Oj 

Sb2 

0.75046 

NiO 

Ni 

0.78524 

Sb^Ss 

Sbg 

0.71438 

NiSO^ 

Ni 

0.37849 

AS2O3 

AS2 

0.75757 

(NHJ^PtCle 

2N 

0.06329 

AS2O5 

AS2 

0.65217 

PbSO, 

Pb 

0.68292 

AS2S3 

AS2 

0.60928 

Pt 

2N 

O.14414 

BaSO^ 

BaO 

0.65654 

Pdl, 

Pd 

0.29448 

BaSO, 

Ba 

0.58790 

Mg2P2G, 

2P 

0.27852 

BiaOj 

2Bi 

0.80654 

Mg2P,G, 

P2O5 

0.63756 

KBFI4 

B 

0.08683 

U,P,0„ 

P2O5 

O.I9817 

AgBr 

Br 

0.42556 

CNH,)2PtCle 

Pt 

0.43911 

CdS 

Cd 

0.77712 

K2SO4 

K2 

0.44898 

CdSO^ 

Cd 

0.53786 

K2SO4 

K2O 

0.54075 

CaO 

Ca 

0.71428 

KaPtClfi 

K2O 

0.19404 

CaS04 

CaO 

O.41158 

AgCl 

Ag 

0.75275 

CO2 

C 

0.27278 

Si02 

Si 

0.47020 

CaCO, 

CO.. 

0.44002 

SiFl, 

Si 

0.57878 

BaC03 

CO.; 

0.22332 

Na2S0, 

Na2 

0.32435 

AgCl 

CI 

0.24725 

Na2S04 

Na20 

0.43674 

Qt,0, 

Cr, 

0.68483 

NaCl 

Na 

0.39408 

CrjOs 

2CVO2 

I. 31520 

BaSOi 

S 

0.13755 

CoO 

Co 

0.78696 

BaSO, 

SO3 

0.34346 

CuO 

Cu 

0.79858 

SrSO, 

Sr 

0  47674 

Cu,S 

CU2 

0.79827 

Tl^PtClfi 

2TI 

0.50046 

CaFl^ 

FI2 

0.48088 

Sn02 

Sn 

0.78681 

BaSiFL 

6F1 

0.40783 

XiO, 

Ti 

0,60065 

Agl 

I 

0.54031 

U3O, 

3U 

0.84873 

Fe^O, 

Fe, 

0.70000 

Vd205 

2Vd 

0.56145 

Fe,03 

2FeO 

0.89999 

W0O3 

Wo 

0.79310 

Li^COs 

Li2 

0.18944 

ZnO 

Zn 

0.80338 

MgO 

Mg 

0.60375 

Zr03^ 

Zr 

0.73913 

'Improvements  in  Methods  of  Chemical  Calculations."    Consult  J.  Anal.  Chem.,  i,  402. 


ENGINEERING   CHEMISTRY 


735 


Specific  Gravity  of  Gases  and  Vapors. 


Gas  or  vapor 


Formula 


Molecular 
weight 


Specific 
gravity 
(air=  I) 


Weight  of  one  liter 

in  grams  at  o°  C 

and  769  m.m 


Acetone 

Acetylene 

Air 

Aldehyde 

Ammonia 

Amylic  alcohol 

Arsenous  anhydride 

Arsine 

Benzene  

Bromine 

Butane • 

Carbon  disulphide 

Carbon  dioxide 

Carbon  monoxide 

Carbon  oxychloride 

Carbon  oxysulphide 

Chlorine  cyanide 

Chloroform 

Cyanogen  

Ethane 

Ethet  

Ether  acetic    

Ethylic  alcohol 

Ethylene • 

Hydrobromic  acid 

Hydrochloric  acid 

Hydrocyanic  acid 

Hpdrofluoric  acid • 

Hydrogen  sulphide  (sulphur 

eted  hydrogen )    

Hydriodic  acid 

Methane 

Methylic  alcohol 

Nitric  oxide 

Nitrous  oxide 

Phosphine       (phosphureted 

hydrogen 

Phosphorus 

Phosphorus  pentachloride  •  • 

Phosphorus  trichloride    

Propane • 

Selenium  hydride 

Silicon  chloride 

Silicon  fluoride 

Steam 

Sulphur  .  . .  • .    

Sulphuric  acid 

Sulphuric  anhydride 

Sulphurous  anhydride 

Tellurium 

Tellurium  hydride 


CgHeO 
Q,H, 

C,H,0 

NH3 

C5H12O 

AS^Og 

AsHg 

CeHe 

Bra 

C4H10 

CS2 

CO2 

CO 

COC12 

COS 

CNCl 

CHCI3 

(CN), 

C,H« 

C4H10O 

C.HgOa 

C^HeO 

C,H, 

HBr 

HCl 

HCN 

HF 

H2S 

HI 

CH, 

CH4O 

NO 

N2O 

PH3 
P4 

PCI5 
PCI3 

SeH., 

SiCl^ 

SiF, 

H2O 

S 

H,SO, 

S63 

SO2 

Te^ 

TeH., 


580 
26  o 

440 
17.0 
88.0 

198.0 
78.0 
78.0 

160.0 
58.0 
76  o 

440 
28.0 
99.0 

60  o 

615 

119  5 
52  o 
300 
74.0 
88.0 
46.0 
280 
81.0 

36.5 
27.0 
20  o 

34.0 

128.0 

16.0 

32.0 

30  o 

440 
340 

124.0 

208.5 

137.5 

44.0 

81.0 

169.5 

104  o 
I8.0 
64.0 
98.0 
80.0 
64.0 
256,0 
130.0 


2  0025 

0  9200 

1  0000 

1  5320 

0.5960 
3.1470 
3.8500 
2.6950 
2.7700 

5  3933 
2.0041 

2  6450 

1  5290 
0.9674 
34163 

2  0748 

2  1244 
4  2150 
I  8064 
I  0366 
2.5650 

3  0670 

1.6133 
0.9674 
2.7310 
1.2474 
0.9456 
06930 

I  1921 
4.4330 
0.5560 
I. 1200 
I  0390 
I  5269 

I  1850 

4-3550 

3.6500 

4.7420 

1.5204 

2.7846 

5.9390 

3.6000 

0.6235 

2.2000 

2.1500 

2.7630 

2.234 

8.9160 

4.5276 


2.5896 

1. 1650 

1.29378 

1.9811 

0.7707 

4.0696 

79105 

3.4851 

3.5821 

6.8697 

2.5914 
3.4204 
1.9662 
I  2510 

4.4174 
2.6828 

2.7473 
4.4507 
2.3360 
1.3404 
3.3170 
3.9662 
2.0862 
1. 2510 
3-5316 
1.6131 
1.2228 

0  8960 

1.5416 
5.7456 
0.7155 
1.4483 
1.3436 

1  9745 

1.5350 
5.6318 
4.7201 
6.1299 
1.9660 
3.6011 
7.6208 

4.6554 
0.8063 

2  8430 
2.7803 

3.5730 

2.8680 

11.5310 

5.8550 


736 


ENGlNEJIvRING   CHEMISTRY 


Equivai^knt  of  Degrees  Baume  and  Specific  Gravity  at  6o= 
FOR  Liquids  Heavier  than  Water. 

U5    ■ 


F. 


Degrees  Baum^  =  I45  — 


sp.  grav. 


Degrees 

Specific 

Degrees 

Specific 

1 
Degrees 

specific 

Degrees 

Specific 

Baum6 

gravity. 

Ban  me. 

gravity. 

Baum^. 

gravity. 

Baura^. 

gravity. 

CO 

I.OOOO 

18.0 

I.1417 

36.0 

1.3308 

54.0 

1.5934 

0.5 

1.0007 

18.5 

1. 1462 

36.5 

1.3364 

54-5 

6022 

I.O 

1.0069 

19.0 

1. 1509 

37.0 

1.3426 

55.0 

611I 

1.5 

I.OI05 

19.5 

I.J555 

37.5 

1.3488 

55.5 

6201 

2.0 

1. 0140 

20.0 

I. 1600 

38.0 

I.3551 

56.0 

6292 

2-5 

I.0175 

20.5 

1. 1647 

38.5 

I.3615 

56.5 

6384 

30 

I.02II 

21.0 

I. 1694 

39.0 

1.3679 

57.0 

6477 

3-5 

1.0247 

21.5 

I.1774 

39.5 

1.3744 

57.5 

6571 

4.0 

1.0284 

22.0 

I.1789 

40.0 

1. 3810 

58.0 

6667 

4-5 

1.0320 

22.5 

1. 1837 

40.5 

1.3876 

58.5 

5763 

5-0 

1.0357 

23.0 

I. 1885 

41.0 

I  3942 

590 

6860 

5-5 

1.0394 

23.5 

I. 1934 

41-5 

1. 4010 

59-5 

6959 

6.0 

1.0432 

24.0 

1.1983 

42.0 

1 .4078 

60,0 

7059 

6.5 

1.0469 

24.5 

1.2033 

42.5 

1. 4146 

60.5 

7160 

7.0 

1.0507 

25.0 

1.2083 

43.0 

1. 4216 

61.0 

7262 

7-5 

1.0545 

25.5 

1. 2134 

43-5 

1.4286 

61.5 

7365 

8.0 

1.0584 

26.0 

1.2185 

44.0 

1.4356 

62.0 

7470 

8.5 

1.0623 

26.5 

1.2236 

44-5 

1.4428 

62.5 

7576 

9.0 

1.0662 

27.0 

1.2288 

450 

1.4500 

63.0 

7683 

9-5 

1. 0701 

27.5 

1.2340 

45-5 

1.4573 

63.5 

7791 

10. 0 

1. 0741 

28.0 

1.2393 

46.0 

1.4646 

64.0 

7901 

10.5 

I. 078 I 

28.5 

1.2446 

46.5 

I.4721 

645 

8012 

II.O 

I.082I 

29.0 

1.2500 

47.0 

1.4796 

65.0 

8125 

II. 5 

I.0861 

29.5 

1.2554  • 

47-5 

1.4872 

65.5 

8239 

12.0 

1.0902 

30.0 

1 . 2609 

48.0 

1.4948 

66.0 

8354 

12.5 

1.0943 

30.5 

1.2664 

48.5 

1.5026 

665 

8471 

13.0 

1.0985 

31.0 

1. 2719 

49.0 

I. 5104 

67.0 

8590 

13-5 

I. 1027 

31.5 

1.2775 

49-5 

I.5183 

67.5 

8710 

14.0 

I. 1069 

32.0 

1.2832 

50.0 

1.5263 

68.0 

8831 

14-5 

I. nil 

32.5 

1.2889 

50.5 

1.5344 

685 

8954 

15.0 

I.II54 

33.0 

1.2946 

5I.O 

1.5426 

69.0 

9079 

15.5 

I.II97 

33-5 

1.3004 

51.5 

1.5508 

695 

9205 

16.0 

I. 1240 

34.0 

1.3063 

52.0 

1.5591 

70.0 

9333 

16.5 

1. 1284 

34.5 

I. 3122 

52.5 

1.5676 

17.0 

1. 1328 

35.0 

1. 3182 

53.0 

1.5761 

17-5 

1. 1373 

35-5 

1.3242 

53-5 

1.5847 

ENGINEERING   CHEMISTRY 


737 


Equivai^ent  of  Degrees  Baume  and 

Specific  Gravity  at  60°  F 

FOR  Liquids  Lighter  than  Water 

Baume 

Weight  in  pounds-6o°  F 

Specific  gravity 

I^iquids  lighter 

than  water 

Per  U.  S.  gal. 

Per  cu  ft 

Per  barrel 
42  gals 

lO 

1. 000 

8-337 

62.368 

350.2 

II 

0993 

8.280 

61.93 

347  7 

12 

0.986 

8.222 

61.50 

345-3 

13 

0.980 

8.171 

61.12 

343-2 

14 

0973 

8.H2 

60.68 

340.7 

15 

0.966 

8.054 

60.25 

338.3 

16 

0-959 

7.996 

59-81 

335.8 

17 

0.952 

7.937 

59-37 

333.4 

18 

0.946 

7.887 

59.00 

331.3 

19 

0940 

7.837 

58.63 

329.2 

20 

0-933 

7.779 

58.19 

326.7 

21 

0.927 

7  729 

57.S2 

324.6 

22 

0.921 

7.679 

57.44 

322.5 

23 

0.915 

7.629 

57.07 

320.4 

■■^4 

0.909 

7.579 

5669 

318.3 

25 

0903 

7.529 

56.32 

316.2 

26 

0.897 

7.479 

55.94 

314.1 

27 

0.892 

7-437 

55.63 

312.4 

28 

0.886 

7-387 

55.26 

310.3 

29 

0.881 

7.345 

54.95 

308.5 

30 

0.875 

7.295 

54.57 

306.4 

35 

0.848 

7.070 

52.89 

296.9 

40 

0.823 

6.862 

51.33 

288.2 

Determination  of  Phosphorus  Pentoxide  in  Calcium  Phosphate. 

Weigh  0.5  gram  of  finely  pulverized  calcium  phosphate,  trans- 
fer to  a  6-inch  porcelain  evaporating  dish,  add  20  cc.  nitric  acid, 
10  cc.  hydrochloric- acid,  and  evaporate  nearly  to  dryness.  Allow 
to  cool,  add  25  cc  nitric  acid,  75  cc.  water,  boil,  and  filter  into  a 
one-fourth  liter  fl^sk  Wash  with  water  until  reaction  is  no 
longer  acid,  and  make  solution  and  washings  up  to  the  containing 
mark  by  the  addition  of  more  water      Temperature  of  solution  =: 

15-5°  C. 

Mix  well  and  take  duplicate  samples,  each  of  25  cc,  transfer 
to  No,  3  beakers,  and  treat  as  follows : 

Concentrate  by  evaporation  to  about  15  cc.     Cool  somewhat, 
and   add   carefully  ammonium   hydroxide  until   the   solution   is 
alkaline,  then  make  reaction  slightly  acid  with  nitric  acid. 
47 


738  e:ngine:kring  chemistry 

Add  50  cc.  of  standard  ammonium  molybdate  solution/  with 
stirring,  and  then  some  more  ammonium  hydroxide,  but  not 
enough  of  the  latter  to  render  the  liquid  alkaline.  Add  20  cc, 
ammonium  molybdate  solution,  and  set  aside  over  night. 

Filter,  test  filtrate  with  a  few  drops  of  ammonium  molybdate 
solution,  to  be  certain  that  all  of  the  phosphoric  acid  is  precipi- 
tated, and  wash  precipitate  well  on  the  filter  with  water  contain- 
ing one-eighth  its  volume  of  ammonium  molybdate  solution. 

The  filtrate  and  washings  are  neglected. 

Fifteen  cc.  ammonium  hydroxide  are  poured  upon  the  filter 
dissolving  the  precipitate;  if  this  it  not  enough  use  more  am- 
monia until  the  precipitate  dissolves  and  the  solution  formed 
is  caught  in  a  No.  2  beaker.  The  filter-paper,  free  from  the  pre- 
cipitate is  washed  thoroughly  with  hot  water,  and  the  filtrate 
and  washings  made  acid  with  hydrochloric  acid.  This  produces 
a  precipitation  of  the  yellow  ammonium  phosphomolybdate.  Am- 
monium hydroxide  is  added  in  quantity  just  sufficient  to  dissolve 
this  and  to  form  a  colorless  solution. 

Thirty  cc.  of  a  standard  magnesia  mixture^  solution  are  now 
added  gradually  with  constant  stirring  for  three  minutes,  and  the 
beaker  with  the  precipitated  ammonium  magnesium  phosphate 
set  aside  for  thirt}^  minutes. 

Filter  upon  an  ashless  filter,  wash  with  water  containing  one- 
eighth  in  volume  of  ammonium  hydroxide,  dry,  ignite  at  first 
with  a  gentle  heat,  finally  at  a  red  heat,  in  a  porcelain  crucible  to 
constant  weight,  and  weigh  as  magnesium  pyrophosphate. 

After  ignition  this  precipitate  should  be  white  or  light  gray  in 
color. 

Example : 

Grams. 

Crucible  -f-  MgaPzOi  15-5567 

Crucible    15.5210 

JMgsPzOi   0.0357 

1  This  solution  is  composed  of  50  grams  MO3,  which  are  dissolved  in  200  cc.  NH4HO— 
200  cc.  HoO,  then  pour  slowly  into  1500  cc.  HNO3  (sp.  gr.  1.2)  with  constant  stirring. 

-  This  solution  is  composed  of  100  grams  MgS04,  100  grams  NH4CI  dissolved  in  800  cc. 
HgO,  400  cc.  NH4HO  (sp.  gr.  0.96)  is  added  thereto  and  thoroughly  mixed. 


ENGINEERING   CHEMISTRY  739 

Then,  Mg.P.Oi  :  P2O.,  : :  0.0357  :  -r 

X  —  0.00283  gram,  from  which  percentage  is  readily  calculated. 
Reference. 
For  a  method  for  complete  analysis  of  phosphates  and  superphosphates 
consult  "Principles  and  Practice  of  Agricultural  Analysis,"  by  H.  W. 
Wiley,  Vol.  II,  ist  edition,  pp.  101-141. 

Determination  of  Iron  in  Hematite   (SnCl2  Method).^ 
The  following  solutions  are  employed  : 

(i)  Potassium  bichromate,  4.9  grams  dissolved  in  i  liter  of 
water;  i  cc.  =  0.005  gram  Fe. 

(2)  Stannous  chloride,  100  grams  dissolved  in  i  liter  of  hydro- 
chloric acid  (500  cc.  strong  acid,  500  cc.  water). 

(3)  Mercuric  chloride,  50  grams  dissolved  in  i  liter  of  water. 

(4)  Potassium  ferricyanide,  a  piece  one-fourth  the  size  of  a 
pea  in  40  cc.  water. 

Weigh  0.500  gram  of  the  ore  into  a  No.  2  beaker,  moisten  with 
water,  add  30  cc.  strong  hydrochloric  acid,  cover  with  a  watch- 
glass,  and  w^arm  gently  until  solution  of  the  iron  is  complete  and 
the  residue  appears  white;  boil,  add  stannous  chloride  from  a 
pipette  till  the  liquid  becomes  colorless,  boil  a  few  minutes,  trans- 
fer solution  to  a  No.  5  beaker,  dilute  with  water  to  300  cc,  add 
35  cc.  mercuric  chloride,  and  stir  .well. 

The  potassium  bichromate  solution  is  now  added  until  4  drops 
fail  to  develop  a  blue  color  with  ferricyanide  indicator  in  one-half 
minute. 

Burette-reading  on  half-gram  samples  of  ore,  gives  the  per 
cent,  of  ore  when  i  cc.  potassium  bichromates  0.005  gram  Fe. 

Precautions. — Avoid  a  large  excess  of  stannous  chloride :  one 
or  two  drops  more  than  is  required  to  destroy  the  yellow  color  of 
the  iron  solution  is  sufficient.  In  adding  mercuric  chloride  solu- 
tion pour  all  in  at  once.  If  added  slowly,  metallic  mercury  is 
precipitated  and  the  operation  spoiled. 

The  stannous  chloride  solution  must  be  added  to  a  concen- 
trated boiling  solution  which  is  strongly  acid  with  HCl  in  order 

1  J.  M.  Wilson,  Chemist  to  Junction  Iron  and  Steel  Co.,  Steubenville,  Ohio,  "Methods 
of  Iron  Analysis,"  p.  16. 


740  e:ngine;e;ring  chemistry 

that  the  reduction  may  take  place  rapidly.  The  excess  of  SnCU 
is  then  oxidized  by  adding  mercuric  chloride,  which  is  too  weak 
an  oxidizing  agent  to  oxidize  any  of  the  ferrous  iron. 

iVn  excess  of  stannous  chloride  easily  reduces  the  mercurous 
chloride  formed  to  the  condition  of  metallic  mercury.  This 
should  never  be  allowed  to  happen  in  an  iron  titration  because 
the  metallic  mercury  is  easily  oxidized  by  the  K2Cr207  and 
would  cause  errors.  Therefore  it  is  particularly  important  in 
the  reduction  by  SnClg,  to  avoid  excess  of  SnCl2  of  more  than 
3  or  4  drops.  The  disappearance  of  the  color  of  the  FeClg  in 
the  solution  affords  a  ready  means  of  observing  when  sufficient 
SnCls  has  been  added. 

The  reduction  by  stannous  chloride  is  very  rapid  and  accurate 
but  requires  care. 

Determination  of  Iron  by  Titration  with  Solution  of 
Potassium  Bichromate. 

A.  Whe:re  the:  Iron  Solution  is  in  the 
Ferrous  Condition. 

Take  1.5  grams  of  crystallized  ammonium  ferrous  sulphate, 
transfer  to  a  No.  3  beaker,  and  dissolve  in  100  cc.  of  cold  water; 
add  10  cc.  dilute  sulphuric  acid. 

Make  a  solution  of  potassium  bichromate  by  dissolving  14.761 
grams  of  the  "C.  P."  salt  in  6*00  cc.  water  in  a  graduated  liter 
flask  and  adding  water  to  the  containing  mark.    Mix  well. 

Each  cubic  centimeter  is  equivalent  to  0.0168  gram  of  iron.    If 
potassium  bichromate  is  added  to  a  solution  of  ferrous  salt  in  the 
presence  of  a  strong  acid,  the  ferrous  salt  is  converted  into  ferric; 
thus, 
6FeSO,  +  ICCr^O,  +  yU.O  = 

3Fe2(SO,)3  +  K,SO,  +  Cr(SO,)3  +7  HA 
With  29.522  grams  of  potassium  bichromate  dissolved  in  2  liters 
of  water,  33.6  grams  of  iron  may  be  changed  from  a  ferrous  to  a 
ferric  salt  (295.22  being  the  molecular  weight  of  K2Cr207  and 
336  being  6  times  the  atomic  weight  of  iron).  One  cc.  of  the  bi- 
chromate solution  corresponds  to  0.0168  gram  Fe  (33.6  -^  2000 
cc.  =  0.0168  gram  Fe). 


e;ngine:e;ring  che;mistry  741 

Fill  a  50  cc.  burette  with  some  of  this  solution,  and  drop  the 
bichromate  slowly  into  the  beaker  containing  the  iron  solution 
until  a  drop  of  the  latter  placed  upon  a  white  porcelain  slab  and 
brought  in  contact  with  a  drop  of  a  very  dilute  solution  of  potas- 
sium ferricyanide,  recently  made,  no  longer  produces  a  blue  or 
greenish  coloration,  showing  the  ferrous  salt  to  be  all  oxidized 
to  ferric  salt.  Note  the  number  of  cubic  centimeters  of  the  bi- 
chromate solution  required  to  do  this,  and  calculate  the  per- 
centage of  iron  in  the  ammonium  ferrous  sulphate. 

Example : 

Ammonium  ferrous  sulphate  taken i-503  gram. 

12.78  cc.  bichromatic  solution  required  to  oxidize. 
T  cc.  =  0.0168  gram  iron. 
12.78  cc,  =  0.2147  gram  iron. 

_,  0.2147  X  100  _  ^    . 

Then =  14.28  per  cent.  iron. 

1.503 

Theoretical  percentage: 

(NHJaSO^FeSO^  +  6H2O  :  Fe  :  :  100  :  x 
X  =  14.28  per  cent. 

B.  Wh^rk  th^  Iron  Soi^utign  Exists  in  th^ 
FERRIC  State:. 

As  the  use  of  bichromate  requires  the  iron  to  be  in  the  ferrous 
condition  so  as  to  be  oxidized  by  the  bichromate,  the  ferric  salt 
is  reduced  to  ferrous  as  follows : 

Take  1.5  grams  of  ferric  sulphate,  transfer  to  a  200  cc.  flask, 
dissolve  in  50  cc.  water,  add  10  cc.  H,2S04,  and  a  few  pieces  of 
granulated  zinc.  All  the  zinc  must  be  dissolved  and  the  solu- 
tion colorless  before  it  can  be  titrated  with  the  bichromate.  If 
the  solution  is  not  colorless,  more  zinc  and  sulphuric  acid  must  be 
added.  It  is  essential  in  this  process,  that  all  the  ferric  salt  be  re- 
duced to  ferrous,  otherwise  the  number  of  cubic  centimeters  of 
the  bichromate  used  would  give  too  low  a  result  for  the  percent- 
age of  iron. 

To  keep  the  iron  solution  in  the  flask  from  oxidizing  while  it  is 
being  reduced  by  the  hydrogen,  from  the  reaction  of  zinc  and 
sulphuric  acid,  several  methods  are  available. 


742  ENGINEERING   CHEMISTRY 

1.  The  method  described  by  Fresenius,  in  which  carbon  dioxide 
is  passed  through  the  flask  during  reduction. 

2.  The  stopper  of  the  flask  is  arranged  to  allow  escape  of  the 
hydrogen  generated  by  the  dissolving  of  the  zinc  by  the  sul- 
phuric acid,  but  prevents  inlet  of  air. 

The  stopper  is  of  rubber  (one  perforation),  through 
which  passes  a  glass  tube.  At  the  upper  end  of  the 
glass  tube  a  piece  of  rubber  tube  (closed  at  b  with  a 
glass  rod)  is  adjusted  and  at  a  an  opening  is  made 
in  the  rubber  tube,  which  allows  the  exit  of  gas,  but 
which  closes  and  prevents  the  entrance  of  air — the 
so-called  Bunsen  valve  (Fig.  A). 

The  reduction  of  the  ion  solution  by  stannous 
chloride  is  to  be  preferred  to  the  reduction  by  means 
of  zinc.    See  page  27. 

Example : 

Ferric  sulphate  taken i  .520  grams. 

18.01  cc.  bichromatic  solution  required  to  oxidize. 

„,  18.01  X  0.0168  X    100  ^      •  •        r         •  -.     1      . 

Then,     =  1990  per  cent,  iron  in  ferric  sulphate. 

Theoretical  percentages: 

FegC  304)3  +  9H2O  :  Feg  :  :  100  :  x 
X  =  19.92  per  cent,  iron  in  ferric  sulphate 

Determination  of  Iron  by  Means  of  a  Solution  of 
Potassium  Permanganate. 

Weigh  1.585  grams  crystallized  KsMugOg  (C.P.),  transfer  to  a 
half-liter  graduated  flask,  dissolve  in  400  cc.  water,  and  add  water 
to  the  containing  mark.  After  solution  and  thorough  admixture, 
I  cc.  of  this  liquid  will  correspond  to  0.0056  gram  Fe.  If  we  add 
a  solution  of  ferrous  salt  containing  an  excess  of  sulphuric  acid 
and  permanganate  of  potassium,  the  former  salt  is  converted  into 
a  ferric  salt  by  the  oxidizing  action  of  the  latter;  thus: 

loFeSO,  -f  8H,SO,  -4-  K.Mn.Og  =: 

5Fe,(SO  js  +  K,SO, -f  2MnSO, -i- 8H,0. 


ENGINEERING   CHEMISTRY  743 

Dissolve  1.5  grams  ammonium  ferrous  sulphate  in  75  cc.  water, 
in  a  No.  3  beaker,  and  add  10  cc.  dilute  sulphuric  acid.  The 
permanganate  solution  is  added  from  a  burette  until  the  liquid  in 
the  beaker  maintains  a  faint  permanent  pink  color.    Thus : 

Example : 

Ammonium  ferrous  sulphate  taken,  1.542  grams. 
Amount  of  K2Mn20s  solution  required  =  39.32  cc. 
I  cc.  K2Mn208  solution  =  0.0056  gram  Fe. 

39.32  cc.  K2Mn20s  solution  =  0.22019  gram  Fe,  or  14.28  per  cent.  Fe 
in  ammonium  ferrous  sulphate. 


INDEX 


Abrasion  cylinder,  269. 

Abrasion  test  for  road  material, 
268. 

Absorption  o£  water  by  rock,  272. 

Absorption  pipette,  Hankee's,  634. 

Absorption  power  of  blotting 
paper,  563. 

Absorption  power  of  building 
stones,  257. 

Absorption  test  for  brick,  268. 

Accelerated  test  for  cement,  225. 

Acetic  acid  in  pigment,  501. 

Acetylene  buoys,  686. 

Acetylene,  candle-power,  684. 

Acetylene,  drying,  684. 

Acetylene,  manufacture,  679. 

Acetylene,  purification,  682. 

Acid,  free,  in  paper,  551. 

Acid,  free,  in  water,  581, 

Acid  resisting  metal,  169. 

Acid  sludge,  325. 

Acid  value  of  varnish,  538. 

Acidity,  lubricating  oils,  386. 

Agalite,  555- 

Ajax  metal,  165. 

Albertite,  274. 

Alizarene,  534. 

Alkali  in  soap,  479,  482. 

Alkalimetric  method  for  phos- 
phorus, 142. 

Alkalinity  in  pigments,  510. 

Alkali  resisting  alloy,  170. 

Alloys,  160. 

Aluminum  bourbonz,  167. 

Aluminum  bronze,   167. 

Aluminum    bronze,    analysis,    170, 

237. 

Aluminum  oxide,  m  cement,   196. 

Aluminum  oxide,  in  clay,  251. 

Aluminum  oxide,  in  cylinder  de- 
posits, 728. 

Aluminum  oxide,  in  fire  sand,  251. 

Aluminum  oxide,  in  iron  ores,  ^2. 

Aluminum  oxide,  in  kaolin,  251. 

Aluminum  oxide,  in  paper,  558. 

Aluminum  oxide,  in  pigments,  509, 

5^3,  515.      , 
Aluminum  oxide,  m  slag,  88. 
Aluminum  oxide,  in  stone,  251. 


Aluminum  oxide  in  water,  570, 
576,  583. 

Aluminum  oxide  in  Welsbach 
mantles,  730. 

Aluminum  paint,  specifications, 
529. 

Aluminum  silicate,  521. 

Aluminum  silver,  170. 

American  cements,  202, 

American  Foundry  Association, 
cast  iron  analysis,  no. 

American  Foundry  Association, 
coke  analysis,  53. 

American  Society  for  Testing 
Material,  cement  specifica- 
tions, 201. 

American  Society  of  Civil  Engi- 
neers, cement  testing,  207. 

Ammonium   nitrate   in    dynamite, 

731. 
Animal  oil,  453. 
Animal    oil   in    cylinder   deposits, 

.  728.  ,  . 
Animal  sizing,  552. 
Anthracene,  325. 

Anthracite  coal,  specifications,  20. 
Anti-friction  metal,  165. 
Antimony  in  alloys,  167. 
Antimony  in  brass  or  bronze,  182. 
Antimony,     rapid     determination, 

.178. 
Antimony  vermillion,  496. 
Apparent  specific  gravity  of  rock, 

272. 
Araeo  picnometer,  368. 
Argentine,  165. 
Arsenic  bronze,  167. 
Arsenic  in  Paris  green,  494. 
Arsenic  in  pyrites,  78. 
Artificial  bitumens,  275. 
Asbestine,  514,  521. 
Asbestos  paints,  530. 
Ash  in  coal,  2,  15,  51. 
Ash  in  coke,  54. 
Ash  in  paper,  554. 
Ash  in  varnish,  538. 
Ashbury  metal,  165. 
Asphalt,  definition,  273,  343. 
Asphalt,  ductility  test,  301,  344. 
Asphalte,  274. 


:46 


INDEX 


Asphaltene,  326. 

Asphalt,  flash  and  fire  test,  311. 

Asphalt,  float  or  fluidity,  298. 

Asphaltic  cement,  346. 

Asphaltic  petroleum,  327,  344, 

Asphalt,  melting  point,  313. 

Asphalt,  oil,  336,  457.^ 

Asphalt  pavement  mixture,  279. 

Asphalt    pavement    specifications, 

340. 
Asphalt,  penetration  test,  295,  343. 
Asphalt,     preliminary     treatment, 

307. 
Asphalt  rock,  339. 
Asphalts,  326. 

Asphalt,  specific  gravity,  271. 
Asphaltum,  274. 
Asphaltum  black,  497. 
Asphaltum  spirits,  522. 
Asphalt,  various  analyses,  276. 
Asphalt,    volatilization    test,    283, 

309,  345- 
Asphalt  v^'earing  surface,  342. 
Atomic  vv^eights  of  elements,  732. 
Atomizers,  steam,  465. 
Atwater-Mahler  Calorimeter,  421. 


B 

B  alloy,  P.  R.  R.,  165. 

B.  t.  u.  values  in  coal,  22. 

B.  t.  u.  determination  by  calorim- 
eter, 2"]. 

Babbitt  metal,  165. 

Bacteriological  examination  of 
water,  600. 

Ball  method  for  cement  consist- 
ency, 230. 

Barium  carbonate  in  pigments, 
508,  513. 

Barium  pigments,  512. 

Barium   sulphate   in   Paris   green, 

495. 
Barium  sulphate  m  pigments,  508, 

521. 
Barytes,  497,  5I2,  521. 
Basic  carbonate  of  lead,  500,  520. 
Basic  sulphate  of  lead,  502,  520. 
Baume  gravity,  327. 
Baume  gravity  tables,  736,  'JZI- 
Bell  metal,  160. 
Benedict  nickel  pipe,  186. 
Benzene,  522. 

Benzol  in  bitumen,  274,  328. 
Benzols,  353. 


Bismuthate  method  for  mangan- 
ese, 137. 

Bitumen,  artificial,  275,  325. 

Bitumen  briquettes,  301. 

Bitumen,  definition,  328. 

Bitumen,  insoluble  in  parafiin 
naphtha,  289. 

Bitumen,  insoluble  in  carbon 
tetrachloride,  291. 

Bitumen,  native,  335. 

Bitumen,  solubility  in  carbon  di- 
sulphide,  285. 

Bituminous  aggregates,  extraction, 

Bituminous  binders,  consistency, 
299. 

Bituminous  coal,  specifications,  22. 

Bituminous  material,  table,  274. 

Bituminous  road  material,  classi- 
fication, 280. 

Bitumens,  distillation  test,  322. 

Bitumens,  melting  point,  313. 

Black  pigments,  497. 

Blanc  fixe,  497. 

Blast  furnace  as  power  plant,  98. 

Blast  furnace  charges,  graphic 
method,  95. 

Blotting  paper,  absorption  quality, 

563. 
Blown  petroleum,  329. 
Blue  pigments,  497. 
Boat  for  steel  analysis,  127. 
Boghead  cannel  coal,  composition, 

16. 
Boiler  compounds,  607. 
Boiler  efficiencies — oil  fuel,  465. 
Boiler  troubles,  621. 
Boiling  point  of  elements,  732. 
Bone  black,  497. 
Bone  fat,  407. 
Brass,  160. 
Brass  analysis,  178. 
Brass,   specifications,   185. 
Brazing  metal,   specifications,    190 
Breaking  point,  oil,  tar  and  pitch, 

352. 
Breaking  strength  of  paper,  556. 
Bremen  blue,  497, 
Brick,  absorptive  power,  257. 
Brick,  crushing  strength,  254. 
Brick,  microscopical  examination, 

263. 
Brick  testing,  260. 
Brick  testing  machines,  261. 
Briquettes,  cement,  261. 


INDEX 


747 


Briquette  molds,  216. 

Bristol  pyrometer,  723. 

Britannia  metal,  165,  168. 

Bronze,  analysis,  178. 

Bronze,  specifications,  193, 

Brown  pigments,  496. 

Brown,  zinc,  specifications,  529. 

Brunswick  blue,  497. 

Brunswick  green,  497. 

Building  stone,  250. 

Bunsen  combustion  furnace,  472. 

Bunsen  photometer,  706. 

Bureau  of  Highways  concrete 
specifications,  246. 

Bureau  of  Standards  sieve  speci- 
fications, 235. 

Burners  for  fuel  oil,  462. 


Cabin  car  color,  specifications,  527. 

Cadmium  yellow,  497. 

Calcium  carbonate,  521. 

Calcium  carbonate  in  Paris  green, 
495. 

Calcium  oxide  in  cement,  196,  238. 

Calcium  oxide  in  clay,  251. 

Calcium  oxide  in  cylinder  de- 
posits, 728. 

Calcium  oxide  in  fire  sand,  251. 

Calcium  oxide  in  iron  ores,  73. 

Calcium  oxide  in  kaolin,  251. 

Calcium  oxide  in  limestone,  66. 

Calcium  oxide  in  paper,  538, 

Calcium   oxide   in   pigments,    509, 

515. 
Calcium  oxide  in  slag,  88. 
Calcium  oxide  in  stone,  251. 
Calcium  oxide  in  water,  570,  576, 

583. 

Calcium  oxide  in  Welsbach  man- 
tles, 730. 

Calcium  phosphate,  analysis,  ']2>'J' 

Calcium  pigment,  509. 

Calcium  sulphate,  521,  522. 

Calcium  sulphate  in  paper,  558. 

Calcium  sulphate  in  water,  576. 

Calcium  sulphide  in  cement,  200. 

Calorific  power  of  blast  furnace 
gas,  104. 

Calorific  value  of  various  oils,  471. 

Calorimeter,  Atwater-Mahler,  421. 

Calorimeter,     cooling     correction, 

30. 

Calorimeter,  Emerson,  34. 


Calorimeter,  Junker's,  665. 

Calorimeter,  oxygen,  27. 

Calorimeter,  Parr,  2>2>' 

CameHa  metal,  165. 

Camp's  agitator,  141. 

Candle-power,   acetylene,  684. 

Candle-power  computer,  718. 

Candles  for  photometry,  711. 

Car  equipment,  for  Pintsch  gas, 
703. 

Car  sampling,  iron  ores,  80. 

Carbene,  329. 

Carbide  feed  generators,  679. 

CarboHc  oil,  353. 

Carbon,  anneaHng,  or  temper,  115. 

Carbon  bisulphide,  329. 

Carbon  dioxide  in  cylinder  de- 
posits, 728. 

Carbon  dioxide  in  flue  gas,  627. 

Carbon  dioxide  in  gypsum,  512. 

Carbon  dioxide  in  illuminating 
gas,  659. 

Carbon  dioxide  in  iron  ores,  74. 

Carbon  dioxide  in  limestone,  68. 

Carbon  dioxide  in  pigments,  502, 
506,  508,  510,  513,  515,  518. 

Carbon  dioxide  in  water,  570,  576, 
598. 

Carbon,  fixed,  in  oils,  332. 

Carbon,  free,  in  oils,  333. 

Carbon,  graphitic,  116. 

Carbon  in  asphalt,  292. 

Carbon  in  cast  iron,  i,  12,  117. 

Carbon  in  coal,  2,  51. 

Carbon  in  coke,  54. 

Carbon  in  oil,  403. 

Carbon  in  steel,  126. 

Carbon  metal,  165. 

Carbon  monoxide  in  flue  gas,  627. 

Carbon  monoxide  in  illuminating 
gas,  661. 

Carbon  residue  in  oil,  402. 

Carbon  tetrachloride,  330. 

Carbureted  water  gas,  670. 

Cardboard  tester,  Schooper,  561. 

Cargo  sampling,  in  iron  ores,  81. 

Castile  soap,  specifications,  489. 

Cast  iron,  no. 

Catalyzers,  127. 

Cellulose  fiber  in  paper,  550. 

Cement,  analysis,  208. 

Cement,  asphaltic,  346. 

Cement,  briquettes,  216. 

Cement,  compressive  strength,  222. 

Cement,  consistency,  212,  228. 


748 


INDEX 


Cement,  constancy  of  volume, 
203,  223. 

Cement,  examination  of,  195,  236. 

Cement,  fineness,  203,  211,  228. 

Cement,  methods  of  testing,  207. 

Cement,  mixing,  231. 

Cement,  Portland,  scheme  for 
analysis,  197. 

Cement,  sampling,  207. 

Cement,  soundness,  231. 

Cement,  specifications,  201,  207. 

Cement,  specific  gravity,  201,  209, 
228. 

Cement,  tensile  strength,  219,  233. 

Cement,  time  of  setting,  215,  231. 

Centrifuge  extractor,  316. 

Cerium  oxide  in  Welsbach  man- 
tles, 730. 

Chalk,  509. 

Chamber  presses,  603. 

Chert,  271. 

China  clay,  497,  514. 

Chinese  blue,  497. 

Chinese  yellow,  496. 

Chlorides  in  paper,  551. 

Chlorine  in  water,  570,  576,  589. 

Chrome  green,  497,  526. 

Chrome  yellow,  497,  523. 

Chromium  in  iron  ore,  75. 

Chromium  in  pigment,  523,  526. 

Chromium  in  steel,  151. 

Clay,  250. 

Cleveland  cup,  383. 

Clinker  in  coal,  52. 

Coal,  anthracite,  specifications,  20. 

Coal,  bituminous,  specifications, 
22. 

Coal,  classification  of  size,  17. 

Coal,  penalization,  24. 

Coal,  proximate  analysis,  i. 

Coal,  sampling,  6. 

Coal,  schedule  of  proposals,  49. 

Coal  tar,  330,  333. 

Coal  tar  black,  497. 

Coal,  tests  for  slate,  17. 

Coal,  value  as  fuel,  50. 

Coal,  value  for  gas  production, 
690. 

Cobalt  blue,  497. 

Cobalt  green,  497. 

Coke,  53. 

Coke,  analysis,  53. 

Coke,  by-product,  693. 

Coke,  composition,  53. 


Coke,  compression  test,  61. 
Coke  oven  tars,  330. 
Coke,  physical  tests,  57. 
Coke,  specifications,  62. 
Cold  test  for  oils,  369. 
Color  of  water,  598. 
Colorimeter,   Stammer,  451. 
Colorimeter,  Wilson,  453. 
Colorimeter,  Wolff's,  592. 
Colorimetric    method    for    carbon 

in  steel,  134. 
Color  test  for  kerosene,  451. 
Combustion    apparatus    for    steel, 

Combustion  method  for  illuminat- 
ing gas,  662. 

Commercial  soaps,  475. 

Compression  of  Pintsch  gas,  701. 

Compression  strength  for  cement, 
22.2. 

Compression  test  of  concrete,  245. 

Compressor  oil,  431. 

Concrete,  242. 

Concrete,  oil-mixed,  247. 

Concrete  pavement  specifications, 
246. 

Condenser  tubes,  specifications, 
188. 

Cone  sampling,  83. 

Consistency  of  bituminous  bind- 
ers, 299. 

Consistency,  normal  of  cement, 
212,  229. 

Constancy  of  volume,  cement, 
203,  223. 

Conversion  tables,  per  cent,  ele- 
ments and  radicals  in  com- 
pounds, 734. 

Copper  analysis,  91, 

Copper  blue,  497. 

Copper  green,  497. 

Copper  in  brass,  161,  179. 

Copper  in  copper  slags,  162. 

Copper  in  ores,  92. 

Copper  in  Paris  green,  495. 

Copper  in  pyrites,  78. 

Copper  in  steel,  148. 

Copper  oxide  in  cylinder  deposits, 
728. 

Copper  pipe,  specifications,   191. 

Copper,  rolled,  specifications,  191. 

Copper  specifications,  185. 

Corrosion,  cause  and  cure,  621. 

Cotton  fiber  in  paper,  550. 


INDEX 


749 


Cracked  oils,  331. 

Creosote  oils,  354,  356. 

Cross  breaking,  paving  brick,  264. 

Crusher   run  stone,  271. 

Crushing  of  paving  brick,  265. 

Crushing     strength     of     building 

stones,  254. 
Cupro,  magnesium,   168. 
Cuprous  chloride  pipette,  657. 
Cut  back  products,  331. 
Cutting  oils,  427. 
Cyanides,    analysis,    729, 
Cyanogen  in  cyanides,  729. 
Cylinder  deposits,  analysis,  728. 
Cylinder  oil,  423. 
Cylinder      oil      specifications,  413. 

.425. 
Cylinder  stock,  422. 


Dead  oils,  331. 

Degras   oil,  409. 

Dehydrated  tar,  332. 

Delta  metal,  163. 

Density  and  calorifific    power    in 

oils,  417. 
Deoxidation  of  brass,  163. 
Deoxidized   bronze,    165. 
Department  of  Docks  and  Ferries, 

New  York,   oil   specifications, 

413. 
Derveaux  water  purifier,  600. 
Destructive  distillation,  332. 
Didymium     oxide,     in     Welsbach 

mantles,  730. 
Direction  of  fiber  in  paper,  566. 
Distillation,  creosote  oil,  357. 
Distillation,  light  oil,  352. 
Distillation  test  for  bitumens,  322. 
Distillation    test,    turpentine,    539. 
Dolomite,  70. 

Doolittle   viscosimeter,   381. 
Dow  form  of  briquette  mold,  306. 
Drying   acetylene,   684. 
Drying  oil  in  creosote  oil,  356. 
Ductility  of  asphalt,  301,  344. 
Ductility  of  asphalt  cement,  347. 
Dulin  rotarex,  320, 
Dust,  in  paving  material,  271. 
Dynamite,  analysis,   731. 
Dynamo  oil,  430. 
Dynamo  oil,  specifications,  414. 


Eggertz  color  test,    136. 


Eichorn,  araeo  picnometer,  368. 

Elements  controlling  properties  of 
cast  iron,  116. 

Elements,  table,   732. 

Elliott  gas  analysis  apparatus,  628. 

Elongation  resistance  of  paper, 
564. 

Emerald  green,  497. 

Emerson  calorimeter,  34. 

Emulsions,  332. 

Engine  oil,   specifications,  413. 

Engler  viscosimeter,  299,  372,  462. 

Eosene,  534. 

Eschka  Fresenius  method  for  sul- 
phur in  coal,  2. 

Eschka  method  for  sulphur  in  oil, 

474. 

Ether,  petrolic,  337. 

European  cements,  202. 

Eutectic,  Guthrie's,  167. 

Evaporation  test,  turpentine,  539. 

Evolution  titration  method  for 
sulphur  in  steel,  144. 

Explosion  pipette,  663. 

Extraction,  bitumenous  aggre- 
gates, 315. 


Face  sampling,  84. 

Factice,  275. 

Factor  for  specific  gravity  in  oil, 

364. 

Fats  and  fatty  acids,  examina- 
tion, 485. 

Fatty  acids  in  soap,  479. 

Fatty  acids,  melting  point,  395. 

Feed  water  heaters,  611. 

Feed  water  heater,  table  of  sav- 
ing, 622. 

Fenton  white  metal,   165. 

Ferric  oxide  in  cement,  196,  237. 

Ferric  oxide  in  clay,  251. 

Ferric  oxide  in  fire  sand,  251. 

Ferric   oxide   in   iron   ores,    'JQ.. 

Ferric  oxide  in  kaolin,  251. 

Ferric  oxide  in  limestone,  66. 

Ferric  oxide  in  paper,  558. 

Ferric  oxide  in  pigments,  509,  512, 
515,  518. 

Ferric  oxide  in  stone,  251. 

Ferric  oxide  in  water,     570,   576, 

583. 
Ferro  aluminum,    167, 
Ferro  aluminum,  analysis,  173. 
Ferrous  oxide  in  cement,  200. 


750 


INDDX 


Ferrous  oxide  in  slag,  88. 

Ferro-tungsten,   167. 

Fery  radiation  pyrometer,  725. 

Fiber  of  paper,  544. 

Filter    for   steel   analysis,    128. 

Filter  presses,  603. 

Filtration  of  water,  600. 

Fineness,  cement,  203,  211,  229. 

Fineness,  pigments,  500,  515. 

Fire   clays,   composition,   253. 

Fireproof  paints,   530. 

Fire  sand,  250. 

Plash  and  fire  test  for  oils,  382. 

Flash  test  for  asphalt,  311. 

Flash  test  for  asphalt  residuum, 
346. 

Flash  test  for  turpentine,  540. 

Float  test  for  asphalt,  298. 

Flour,  in  paving  material,  271. 

Flue  gas  analysis,  627. 

Flue  gas,  conversion  table,  637. 

Fluidity  test,   for  asphalt,  298. 

Flux,  in  asphalts  and  bitumens, 
332,   345. 

Flux,   paraffin,  279. 

Fluxed  asphaltic  cements,  348. 

Ford  Williams'  method,  mangan- 
ese ores,  90. 

Foster  flash  and  fire  tester,  448. 

Foundry  chemistry,  115. 

Frame   presses,   604. 

Frankfort  black,  497. 

Frankolin,  684. 

Freezing  test  for  stone,  258. 

Friction  coefficient  for  oils,  409. 

Fuel  economizers,  623, 

Fuel  oil,  455. 

Fuel,  testing,  43. 

Furfural,   in   turpentine,    540. 


Gangue,  in  pyrites,  78. 
Gas,  acetylene,  679. 
Gas  analysis,  627. 
Gas,  calorimetry,  665. 
Gas,  chimney  or  flue,  analysis,  627. 
Gas    from   blast    furnaces,    loi. 
Gas  house  coal  tar,  333. 
Gas,  illuminating,  analysis,  655. 
Gas,   natural,   composition,   677. 
Gas,  oil,  manufacture,  695. 
Gas,  Pintsch,  696. 
Gas,  producer,   composition,  676. 
Gas    producing    quality    of    coal, 
691. 


Gas,  variation  in  volume,  table, 
714. 

Gas,  water,  670. 

Gases,   density,  654. 

Gases,  specific  gravity,  735. 

Gases,  various  illuminating,  com- 
position, 675. 

Gasolene  test  for  oils,  401. 

Generators,    acetylene,   679. 

German  silver,  167. 

Gilsonite,  274,  333. 

Glycerine  in  fats  and  soaps,  486. 

Glycerine  soaps,  490. 

Glycerine  specifications,  492, 

Goubert  feed  water  heater,  612. 

Grain,  116. 

Graduation  of  sand  in  concrete, 
246. 

Grading  mineral  aggregate  in  bi- 
tumens, 319. 

Grahamite,   274,   333. 

Granite,  absorptive  power,  257. 

Granite,    crushing    strength,    254, 

257. 
Granite,  in  road  material,  271 
Granitoid,  271. 
Graphic  method  for  blast  furnace 

charges,  95. 
Graphite,  as  lubricant,  415. 
Graphite  black,  497. 
Graphite,  in  cast  iron,   114. 
Graphite,   specifications,   417. 
Gravimetric  method  for  nickel  in 

steel,   149. 
Greases,  406. 

Greases,  various,  composition,  407. 
Green  fuel  economizer,  623. 
Green  pigments,  497. 
Guide  gibs,  190. 
Gumming  test  for  oils,  398. 
Gums   in   varnish,   537. 
Gun  metal,   160. 
Guthrie's   eutectic,    167. 
Gypsum,  497. 
Gypsum,   analysis,   511. 


Hahn,  gas  analysis  apparatus,  636. 
Hankee's  absorption  pipette,  634. 
Hann's  method   for  iodine  value, 

453. 
Harcourt  pentone  lamp,  716, 
Hardening    and     tempering     oils, 

431- 
Hardness   of  water,   584. 


IND^X 


751 


Hardware  metal,  168. 

Hartig  Reusch  apparatus,  557, 

Heating  asphalt  cement,   347. 

Heat  loss  in  chimney  gases,  650. 

Heidenreich's  test,  439. 

Hematite,  71. 

Hemp  fiber  in  paper,  550. 

Hempel  burette,  U.  G.  I.  modi- 
fication, 656. 

Heraeus  quartz  glass  thermom- 
eter,  719. 

Heratol,  683. 

High  carbon  tars,  334. 

Hogarth  flask,  58. 

Horse-power  developed,  table  of, 
676. 

Howard  and  Morse,  apparatus  for 
consistency  of  binders,  300. 

Huble,   iodine  absorption,  381. 

Hydraulic  bronze,    168. 

Hydraulic  compression  machine 
for  cement  and  concrete,  243. 

Hydraulic  metal,  169. 

Hydrogen  in  illuminating  gas,  662. 

Hydrometer,        Koppe-Saussure's, 

557- 
Hydrometer,  Sohmer,  281. 
H)^droxide,  in  cyanides,  729. 
Hygrometer,  Tutwiler  and  Bond, 

658. 


Ice  machine  oils,  428. 

Ignition  loss  in  pigments,  506,  509, 

■512,  514. 
Illuminating  gas,  655. 
Impact  test,  concrete,  248. 
Impact  test,  paving  brick,  266. 
Impact  tester,  270. 
Incrustation,  cause  and  cure,  621. 
Indian  red,  496. 
Indian  red,  specifications,  528. 
Insoluble  iron  ores,  75. 
Insoluble  matter  in  pigments,  503, 

507,  508,  512,  514,  531. 
Interpretation     of     cement     tests, 

224. 
Iodine  absorption,  oils,  381. 
Iodine  value,  linseed  oil,  453. 
Iron  determinations,  738,  739,  740, 

741. 
Iron  in  brass  or  bronze,  183. 
Iron  in  cylinder  deposits,  728. 
Iron  in  pigment,  512,  532. 
Iron  in  pyrites,  78. 


Iron  in  tin  plate,  158. 
Iron  ores,  analysis,  71. 
Iron  ores,   composition,   ^T. 
Iron  ores,  sampling,  80. 
Iron  oxide  paint,  496. 
Isolite,  703. 


journal  boxes,  190. 

Junker's  gas  calorimeter,  665. 

Jute  fiber  in  paper,  550. 


Kaolin,  250,  497. 

Kayserzinn,  170. 

Keith  gas,  695. 

Kennicott  process  for  water  soft- 
ening, 609. 

Kerosene,  441. 

King's  yellow,  497. 

Koppe-Saussure's  air  hydrometer, 
557. 


Lamp  black,  497. 

Lanthanum  oxide  in  Welsbach 
mantles,  730. 

Lard  oil,  specifications,  388. 

Laundry  soaps,  475. 

Lead  analysis,  92. 

Lead  chromate  in  Paris  green, 
495. 

Lead  covered  sheets,  154. 

Lead  in  brass  or  bronze,  179. 

Lead  in  lead  covered  sheets,   157. 

Lead  in  ores,  93, 

Lead  in  pigments,  500,  502,  504, 
5 16,  523. 

Lead  in  pyrites,  78. 

Lead  in  tin  plate,  157. 

Lead  peroxide  in  pigments,  516. 

Lead,  pig,  specifications,  194, 

Lead  sulphate,  in  Paris  green, 
495- 

Lead  sulphate  in  pigment,  526. 

Lead  sulphate  paint,  496. 

Le  Chatelier,  specific  gravity  ap- 
paratus, 210. 

Le  Chatelier,  pyrometer,  ^22. 

Leeds  scheme  for  soap  analysis, 
477- 

Lemon  chrome,  analysis,  523, 

Liebermann-Storch  reaction,  397. 

Lignites,  14. 


752 


INDEX 


Lime,  hydrated,  in  paint,  512. 

Lime  in  Portland  cement,  199, 
200. 

Limestone,  65. 

Limestone,  absorptive  power,  257. 

Limestone,  analysis,  66. 

Limestone,  crushing  strength,  254. 

Limonite,  71. 

Limpid  point,  356. 

Linen  fiber  in  paper,  550. 

Linoxyn,  in  varnish,  537. 

Liquids,  specific  gravity  and  de- 
grees Baume,  736. 

Lithopone,  496,  507,  520. 

Locomotive  water,  606. 

London  coal  gas,  calorimetric 
tests,  669. 

Low  carbon  tars,  334. 

Lowe  process  gas,  composition, 
670. 

Lowe  water  gas  apparatus,  672. 

Lubricants,  421. 

Lubricating  oils,  examination,  362. 

Lye,  concentrated,  specifications, 
492. 


Macadam,  toughness  test,  269. 

Magnesite,  497. 

Magnesium  as  deoxidizer,  163. 

Magnesium  oxide  in  cement,  198, 
238. 

Magnesium  oxide  in  clay,  251. 

Magnesium  oxide  in  cylinder  de- 
posits, 728. 

Magnesium  oxide  in  fire  sand,  251. 

Magnesium  oxide  in  iron  ores,  73. 

Magnesium  oxide  in  kaoHn,  251. 

Magnesium  oxide  in  limestone,  66. 

Magnesium  oxide  in  paper,  558. 

Magnesium  oxide  in  pigments, 
510,  515.       , 

Magnesium  oxide  m  pyrites,  78. 

Magnesium  oxide  in  slag,  88. 

Magnesium  oxide  in  stone,  250. 

Magnesium  oxide  in  water,  570, 
576,  583.       .         .  ,  ^     , 

Magnesium  oxide  in  Welsbach 
mantles,  730. 

Magnesium  silicate,  521. 

Magnesium  silicate  in  paper,  558. 

Magnetite,  71. 

Magnolia  metal,  165. 

Malachite,  497. 

Maltha,  274,  334. 


Malthene,  334. 
Manganese  bronze,  167,  189. 
Manganese  brown,  496. 
Manganese  green,  497. 
Manganese   in   cast   iron,    ill. 
Manganese  in  pyrites,  78. 
Manganese  in  steel,  137. 
Manganese    ores,    Ford   Williams 

method,  90. 
Manganese  oxide  in  clay,  251. 
Manganese  oxide  in  fire  sand,  251. 
Manganese  oxide  in  iron  ores,  73. 
Manganese  oxide  in  kaolin,  251. 
Manganese  oxide  in  slag,  88. 
Manganese  oxide  in  stone,  251. 
Manganese  resistance  metal,  169. 
Manganin,  169. 

Manganous  oxide  in  cement,  200. 
Manheim  gold,   163. 
Mantles,  Welsbach,  analysis,   730. 
Marble,  absorptive  power,  257. 
Marble,   crushing  strength,  254. 
Marsh  gas,  274. 
Massie's  test,  439. 
Matrix,  271. 
Maumene's  test,  389. 
Mechanical  burners,  463. 
Medicated  soaps,  475. 
Melanin,  496. 

Melting  point  in  bitumens,  113. 
Melting  point  of  elements,  732. 
Melting  point  of  fatty  acids,  395. 
Melting    point    of    oils,    tars    and 

pitches,  350. 
Mercury  sulphide,  533. 
Merten's  machine  for  friction  of 

oils,  411. 
Methane,   662. 
Aleyer  tube,  131. 
Microscopical       examination      of 

brick,  263. 
Microscopical  examination  of  oil, 

402. 
Alicroscopical       examination      of 

paper,  548. 
Mineral    aggregate,    in    bitumens, 

319- 
Mineral  green,  497. 

Mineral    matter   in   water,    583. 
Mineral   oil   in   cylinder   deposits, 

728. 
Mineral  rubber,  335. 
Mixed  lead  pigment,  analysis,  524. 
Mixing  asphaltic  cement,  346. 


IND^X 


753 


Mixing  cement,  231. 
Mixtures,  asphalt,  345. 
Moisture  in  coal,  i,  51. 
Moisture  in  coke,  54. 
Moisture  in  gypsum,  511. 
Moisture  in  iron  ores,  71. 
Moisture    in    pigments,    500,    506, 

507,  509,  512,  514,  S16,  531. 
Molds     for     bitumen     briquettes, 

306. 
Molds,  for  cement  briquettes,  217. 
Molybdate   magnesia  method   for 

phosphorus,  140. 
Monel  metal,  194. 
Mortar,  absorptive  power,  257. 
Mosaic  gold,  163. 
Motor  oils,  432. 
Mucus,  organic,  496. 
Muntz's  metal,  160,  191. 


Naphthas,  335,  522. 

Naphthalene,    335,    353,    356. 

Naphthalene,  in  bitumens,  274. 

Native  bitumens,  335. 

Natural  cement,   195. 

Natural  cement,  constancy  of  vol- 
ume, 204. 

Natural  cement,  fineness,  204. 

Natural  cement,  specifications,  204. 

Natural   cement,   tensile   strength, 
204. 

Natural   cement,  time   of  setting, 
204. 

Natural  gas,  composition,  677. 

Neatsfoot  oil,  specifications,  414. 

Needle  metal,  169. 

Nessler  reagent,  589. 

Newbigging's  plant   for  gas  pro- 
ducing quaUty  of  coal,  691. 

New  York  State  tester  for  flash 
point,  312. 

Nickel's  apparatus  for  paper  fiber, 
566. 

Nickel  in  pyrites,  78. 

Nickel  in  steel,  149. 

Nitrates  in  dynamite,  731. 

Nitrates  in  water,  594. 

Nitrites  in  water,  595. 

Nitrogen  in  flue  gas,  627. 

Nitrogen  in  illuminating  gas,  662. 

Nitrogen  in  oil,  473. 

Nitrogen  in  Prussian  blue,  532. 

Nitroglycerine  in  dynamite,  731. 
48 


Nitrosulphuric  method  for  silicon 
in  steel,  146. 

Nomenclature,  standard,  for  pig- 
ments, 520. 

Non-bituminous  road  materials, 
271. 

Non-fluid  oils,  408. 


Oil  asphalts,  336. 
Oil,  calorific  power,  417. 
Oil,  carbolic,  353. 
Oil    containing    blown    rape    seed 
and  blown  cotton  seed  oil,  435. 
Oil,  drying,  in  creosote  oil,  356. 
Oil  for  wood  block  pavement,  359. 
Oil,  fuel,  455. 
Oil  gas,  695. 

Oil  in  cylinder  deposits,  728. 
Oil,  lard,  specifications,  388. 
Oil,  linseed,  453. 
Oil,  mineral  sperm,  specifications, 

451- 
Oil  mixed  concrete,  247. 
Oil,  nitrogen  determination,  473. 
Oil  pitches,  336. 
Oil,  sulphur  in,  474. 
Oil  tars,  336. 
Oils,  animal,  453, 
Oils,  breaking  point,  352. 
Oils,  burning,  cloud  test,  443. 
Oils,  burning,  flash  and  fire  test, 

442. 
Oils,  compressor,  431. 
Oils,  cracked,  331. 
Oils,  creosote,  354,  356. 
.Oils,  cutting,  428. 
Oils,  cylinder,  423. 
Oils,  dead,  331. 
Oils,  dynamo,  430. 
Oils,    hardening    and    tempering, 

431. 
Oils,  ice  machine,  428. 
Oils,   illuminating,  441. 
Oils,  lubricating,  acidity,  386. 
Oils,    libricating,    carbon    residue, 

402. 
Oils,     lubricating,     coefficient     of 

friction,  409. 
Oils,  lubricating,  cold  test,  369. 
Oils,    lubricating,    emulsion    test, 

433. 
Oils,  lubricating,  examination,  362. 


754 


IND^X 


Oils,  lubricating,  fatty  oil  mix- 
tures, 440. 

Oils,  lubricating,  fixed  carbon,  403. 

Oils,  lubricating,  flash  and  fire 
,     test,  382. 

Oils,  lubricating,  gasolene  test, 
401. 

Oils,  lubricating,  gumming  test, 
398. 

Oils,  lubricating,  heat  test,  433. 

Oils,  lubricating,  iodine  absorp- 
tion, 382. 

Oils,  lubricating,  Maumene's  test, 

389. 

Oils,  lubricating,  microscopical  ex- 
amination, 402. 

Oils,  lubricating,  paraffin  deter- 
mination, 403. 

Oils,  lubricating,  soap  test,  404. 

Oils,   lubricating,   specific  gravity, 

363. 

Oils,  lubricating,  sulphur  test,  399. 

Oils,  lubricating,  water  test,  400. 

Oils,  melting  point,  351. 

Oils,  motor,  432. 

Oils,   paraffin,  422. 

Oils,  rosin,  detection,  397. 

Oils,  specific  gravity,  350,  355. 

Oils,  spindle,  422. 

Oils,  testing,  349. 

Oils,  transformer,  428. 

Oils,  turbine,  427. 

Oils,  vegetable,  453. 

Oils,  ultimate  analysis,  472. 

Olefiants  in  illuminating  gas,  660. 

Olefine,  457. 

Olsen  impact  tester,  270. 

Orange   pigments,  497. 

Organic  color,  in  pigments,  516. 

Organic  lakes,  534. 

Organic  matter  in  limestone,  66. 

Organic  matter  in  water,  583,  596. 

Orsat  gas  apparatus,  632. 

Orthoanisodine,  534. 

Oven,  N.  Y.  Testing  Laboratory, 
284. 

Oxidation  method  for  sulphur  in 
steel,   144. 

Oxyacetylene  welding,  689. 

Oxygen,  dissolved  in  water,  598. 

Oxygen,  for  calorimeter  combus- 
tion, 28. 

Oxygen  in  flue  gas,  627. 


Oxygen  required  for  gas  combus- 
tion, 641. 
Ozlo  white,  506. 
Ozocerite,  274. 


Packfong,   167. 
Paper,  acids  in,  551. 
Paper,  analysis,  558. 
Paper,  ash,  554. 
Paper,  breaking  strength,   556. 
Paper,  chemical  and  physical  ex- 
amination, 544. 
Paper,  direction  of  fiber,  566. 
Paper,   elongation  resistance,   564. 
Paper,  microscopical  examination, 

548. 

Paper,  nature  of  fiber,  544. 

Paper,  Paris  Chamber  of  Com- 
merce tests,  562. 

Paper,  sizing,  552. 

Paper,  thickness,  556,  567. 

Paper,  weight,  556,  567. 

Paraffine,  336,  457- 

Paraffine  flux,  279. 

Paraffine  in  bitumens,  274. 

Paraffine  in  dynamite,  731. 

Paraffine  in  illuminating  gas,  662. 

Paraffine  in  oils,  403. 

Paraffine  naphthas,  336. 

Paraffine  petroleums,  336. 

Paraffine  scale  in  asphalt,  293,  336. 

Paraffine  spirits,  522. 

Parallel  system  of  sampling,  80. 

Para-nitraniline,   534. 

Paris  green,  analysis,  494. 

Paris  white,  509. 

Parr  calorimeter,  33. 

Parsons,  white  metal,  165. 

Paste,  cleaning  and  polishing,  493. 

Pats,   cement,   224. 

Pattern  metal,   169. 

Paving  brick,  testing,  264. 

Penalization  of  coal,  24. 

Penetration  test  for  asphalt,  295, 
343,  344,  345. 

Penetration  test  for  asphalt  ce- 
ment, 346,  347,  348. 

Penetrometer,  296. 

Penn.   anthracite,   analysis,   16. 

Pennsylvania  R.  R.  cabin  car 
color,  527. 

Pensky  Martin  closed  cup,  384. 

Peroxide  fusion  method  for  sul- 
phur,  5. 


IND^X 


755 


Persulphate  method  for  mangan- 
ese in  steel,  139. 

Petrolene,  337. 

Petroleum  burning  oils,  specifica- 
tions, 442. 

Petroleum  products,  tarry  matter 
in,  405. 

Petroleums,  337. 

Petrolic  ether,  337. 

Pewter,  165. 

Phono  electric  wire,  168. 

Phosphor  bronze,   165,   193. 

Phosphorus   in  cast  iron,   ill. 

Phosphorus  in  coal,  6. 

Phosphorus  in  coke,  56. 

Phosphorus  in  steel,  40. 

Phosphorus  pentoxide  in  calcium 
phosphate,  737. 

Phosphorus  pentoxide  in  cement, 
200. 

Phosphorus  pentoxide  in  iron 
ores,  ^2. 

Phosphorous  pentoxide  in  lime- 
stone, 66. 

Phosphorus  pentoxide  in  slag,  88. 

Photometer,  Bunsen,  706. 

Photometer,  standard  bar,  715. 

Photometry,  705. 

Physical  characteristics  of  pig- 
ments, 520. 

Physical  tests  on  coke,  57. 

Physical  tests  on  quicklime,  241. 

Pig  iron,  114. 

Pig  iron  composition,   115. 

Pig  iron  sampling,  125. 

Pig  iron,  specifications,  124. 

Pig  lead,  specifications,   194. 

Pinchbeck,  163. 

Pintsch  gas,  696. 

Pintsch  gas  apparatus,  697. 

Pintsch  gas  compression,  701. 

Pintsch    gas    purification,    700. 

Pintsch  hydrocarbon,   698. 

Pintsch  tar,  698. 

Pipe,  brass,  specifications,  185. 

Pitch,  breaking  point,  352. 

Pitches,  337. 

Pitch,  melting  point,  350. 

Pitch,  specific  gravity,  350. 

Pitch,  testing,  349. 

Plaster  of  Paris,  analysis,  510. 

Platinoid,  169. 

Polymerization,  of  turpentine,  539. 

Porter  Clark  process,  604. 


Portland  cement,  195. 

Portland     cement,     constancy     of 

volume,  205. 
Portland  cement,  definition,  205. 
Portland  cement,  fineness,  205.^ 
Portland  cement,  specific  gravity, 

205. 
Portland    cement,    sulphuric    acid 

and  magnesia  in,  205. 
Portland  cement,  tensile  strength, 

205. 
Portland  cement,  time  of  setting, 

205. 
Potash,  in  cement,  200,  239. 
Potash,  in  clay,  fire  sand,  kaolin 

and  stone,  252. 
Potash,  in  water,  576. 
Potash   specifications,  491. 
Potassium,  in  cyanides,  729. 
Potassium     nitrate    in    dynamite, 

731. 
Powder   from   blast   furnace   gas, 

ig8. 
Priming,  cause  and  cure,  621. 
Producer  gas,  composition,  676. 
Prussion  blue,  497. 
Prussian  blue,  analysis,  531. 
Prussian    blue    in  •  chrome    green, 

526. 
Puratylene,  683. 
Purification   of   acetylene,   682. 
Purification  of  Pintsch  gas,  700. 
Pyrites,    composition    of    various^ 

79- 
Pyrites,  scheme  for  analysis,  78. 
Pyro  bitumens,  275,  337. 
Pyrogenetic,  338. 
Pyrometers,    electrical    resistance 

type,  719. 
Pyrometers,    optical    and    radition 

type,  725- 
Pyrometers,   thermo   electric,   722. 
Pyrometry,  718. 
Pyroxylene  in  dynamite,  731. 


Qualitative  tests  for  alloys,  174. 
Quantitative  tests  for  alloys,   175- 
Quickhme  in  paint,  512. 
Quicklime,   sampling,   240. 
Quicklime,  specifications,  240. 
Quickhme,  testing,  240. 


Rattler,  for  brick,  265. 


756 


IND^X 


Reagents  for  steel  analysis,  128. 

Realgar,  497. 

Red  chromate  of  lead,  analysis, 
524. 

Red  lead,  496. 

Red   lead,   analysis,   515. 

Red   lead,    specifications,   525. 

Red  lead,  volumetric  determina- 
tion, 524. 

Red  pigments,  496. 

Reduced  oils,  338. 

Reduced  petroleums,  338. 

Redwood    viscosimeter,    380. 

Refined  tar,  338. 

Refractive  index  of  turpentine, 
539. 

Requirements,  state,  for  flash  and 
fire  test  of  oils,  450. 

Residual  oils,  338. 

Residual  tar,  338. 

Residuum,    petroleum,    280. 

Residuum,    semi-asphaltic,   346. 

Residuums,  asphaltic,  345. 

Residuums,  paraffine,  346, 

Resin,  in  dynamite,  731. 

Resin,  in  shellac,  541. 

Resin,  in  soap,  482. 

Resin  soaps,  475. 

Resin    specifications,    492. 

Retorts  for  Pintsch  gas,  699. 

Riehle  cement  tester,  221. 

Riehle  friction  apparatus  for  oils, 
410. 

Road  material,  abrasion  test,  268. 

Road  material,  bituminous,  exam- 
ination, 280. 

Rock  asphalt,  339. 

Rope  net  system  of  sampling  iron 
ores,  81, 

Rose  metal,  165. 

Rosin  oils,  detection,  397. 

Rosin,  sizing,  552. 

Rosine,  167. 

Rotarex,  Dulin,  320. 

Round  sampling,  84. 

Rubble,  271. 

S 

Salt  water  soap,  specifications,  489. 
Samples,   asphaltic  cement,   348. 
Sampling  cement,  207. 
Sampling  coal,  6. 
Sampling  coke,  53. 
Sampling  iron  ores,  80. 


Samphng  lead  covered  sheets,  154. 

Sampling  pig  iron,  125. 

Sampling   quicklime,   241. 

Sampling  tin  plate,   154. 

Sand,    for    concrete,    tests,   245. 

Sand,  standard,  215. 

Sandsaone,  absorptive  power,  257. 

Sandstone,  crushing  strength,  254. 

Saponification   value,   405. 

Saybolt  flash  and  fire  tester,  450, 

Saybolt  viscosimeter,  374. 

Scale  forming  ingredients  in 
water,  583. 

Scarlet,   534. 

Schedule,  coal  proposals.  Treas- 
ury Department,  49. 

Schooper,  cardboard  tester,  561. 

vSchwartz   U-tube,   472. 

Seger  cones,  726. 

Semi-asphaltic  petroleum,  339. 

Separation  of  mineral  from  vege- 
table and   animal  oil,  391. 

Sepia,  496. 

Shellac  analysis,  541. 

vShot  metal,  165. 

Sienna,  497. 

Sieve   shaker,   321. 

Sieve  specifications,  235. 

Silex,  514. 

Silica,  in  building  stone,  250. 

Silica,  in  cement,  196,  236. 

Silica,  in  clay,  250. 

Silica,  in  cylinder  deposits,  728. 

Silica,  in  iron  ores,  71. 

Silica,  in  kaolin,  250. 

Silica,  in  limestone,  66. 

Silica,  in  paper,  558. 

Silica,  in  pigment,  515,  518. 

Silica,  in  slag,  88, 

Silica,  in  water,  570,   576,  583. 

Silica  pigments,   514,   522,   530. 

Silicon  bronze,    167. 

Silicon  in  cast  iron,    no,    121. 

vSilicon  in  steel,  146. 

Sizing,  in  paper,  552. 

Slag,  blast  furnace,  analysis,  88. 

Slag,  broken,  mechanical  analysis, 

Slags,  blast  furnace,  composition, 

89. 
Slate,  in  coal,  17. 
Soap  analysis,  475. 
Soap  analysis  scheme,  Leeds,  477. 
Soap  analysis  scheme,  Wright  and 

Thompson,  478. 


INDEX 


757 


Soap,  Castile,  489. 

Soap,  mineral,  491. 

Soap  powder,  490. 

Soap,  salt  water,  489. 

Soap,  specifications,  488. 

Soap  test,  for  oils,  404. 

Soaps,  glycerine,  490. 

Soaps,  transparent,  489. 

Soaps,   various,    composition,   487. 

Society     of     Chemical     Industry, 

cement  analysis,   236. 
Soda  or  sodium  oxide  in  cement, 

200,  239. 
Soda   or    sodium   oxide    in    clay, 

252. 
Soda  or  sodium  oxide  in  fire  sand, 

252. 
Soda  or  sodium  oxide  in  kaolin, 

252. 
Soda   or   sodium   oxide  in  paper, 

558. 
Soda   or    sodium   oxide   in   stone, 

252. 
Soda   or   sodium   oxide  in  water, 

576. 
Soda,  specifications,  491. 
Sodium  in  cyanide,  729. 
Sodium  potassium  cyanide,  analy- 
sis, 729. 
Sodium  nitrate  in  dynamite,  731. 
Soft  bearing  metal,  170. 
Sohmer  hydrometer,  281. 
Soil,  in  road  material,  272. 
Solder,    160. 
Solder,  soft,  165. 
Soluble  salts  in  gypsum,  511. 
Soluble  salts  in  pigments,  507. 
Sorge  Cochrane  hot  process  feed 

water  softner,  615. 
Soundness,  of  cement,  231. 
Spanish   white,   509. 
Spathic  iron  ores,  71. 
Spawl,   in   road  material,   272. 
Specific  gravity,  asphalt  residuum, 

346.     . 
Specific  gravity,  asphalts,  281,  327. 
Specific  gravity,  cement,  201,  209. 
Specific    gravity,    coal    and    coke, 

57. 
Specific  gravity,  creosote  oil,  357. 
Specific  gravity,  elements,  732. 
Specific  gravity,   fuel  oil,  460. 
Specific  gravity,  gases  and  vapors, 

735- 


Specific  gravity,  linseed  oil,  453. 
Specific  gravity,  liquids,  736,  ^n. 
Specific    gravity,    lubricating    oil, 

363. 
Specific  gravity,  oil,  tar  and  pitch, 

350- 
Specific    gravity,    oils    used    with 

mineral  oils,  table,  369. 
Specific  heat,  of  elements,  732. 
Specifications,      aluminum     paint, 

529. 
Specifications,    asphalt    pavement, 

340. 

Specifications,  brass,  bronze  and 
copper,   185. 

Specifications,  brass  castings,   185. 

Specifications,  brass  pipe,   185. 

Specifications,  brazing  metal,   190. 

Specifications,  brown  zinc,  529. 

Specifications,   burning  oils,   442. 

Specifications,  cabin  car  color,  527. 

Specifications,  cement,  201,  226. 

Specifications,  chrome  green,  526. 

Specifications,  chrome  yellow,  523. 

Specifications,  cleaning  and  polish- 
ing paste,  493. 

Specifications,   coal,   20,  46. 

Specifications,  coke,  62. 

Specifications,  concentrated  lye, 
492. 

Specifications,  concrete  pavement 
and  curb  foundations,  246. 

Specifications,  condenser  tubes, 
188. 

Specifications,  copper  pipe,   191. 

Specifications,    cylinder    oil,    413, 

425. 
Specifications,  dynamo  oil,  414. 
Specifications,    engine    oil,    413. 
Specifications,  fuel  oil,  459. 
Specifications,   glycerine,   492. 
Specifications,  guide  gibs,   190. 
vSpecifications,  Indian  red,  528. 
Specifications,  journal  boxes,   190. 
Specifications,  lard  oil,  388. 
Specifications,  linseed  oil,  453. 
Specifications,   manganese   bronze, 

189. 
Specifications,   mineral   sperm   oil, 

451. 
Specifications,  Monel  metal,  194. 
Specifications,  neatsfoot  oil,  415. 
Specifications,  pig  iron,   124. 
Specifications,  pig  lead,  194. 
Specifications,  potash,  491. 


7S8 


INDEX 


Specifications,    quicklime,    240. 

Specifications,  red  lead,  525. 

Specifications,  rolled  bronze,  193. 

Specifications,  rolled  copper,  191. 

Specifications,  sieves,  235. 

Specifications,  soap,  z|88. 

Specifications,  soap  powder,  490. 

Specifications,  soda,  491. 

Specifications,  steel,   126. 

Specifications,  tin  plate,   159. 

Specifications,   turpentine,   540. 

Specifications,  white  lead,  519. 

Specifications,  white  metal,  189. 

Specifications,  white  zinc,  528. 

Specifications,  wood  block  pave- 
ment, 358. 

Speculum  metal,   163. 

Spray  burners,  462. 

Stammer  colorimeter,  453. 

Standardization  of  calorimeter,  28. 

Starch  in  paper,  553. 

Steel  analysis,   126. 

Sterline,   168. 

Sterro,   163. 

Stone,  250. 

Stone,  broken,  mechanical  analy- 
sis, 273. 

Stone  chips,  in  road  material,  272. 

Storage  of  cement  test  pieces,  219. 

Strontianite,   512. 

Strontium  oxide  in  cement,  200. 

Strontium   white,   497,    512. 

Sugg-Argand    burner,    708. 

Sulphates,   in   g>'psum,    511. 

vSulphates,  in  paper,  551. 

Sulphates,  in  pigments,  503,  510, 
513,  515,  518,  523. 

Sulphates,  in  water,  570,  576,  583. 

Sulphonation  test,  357. 

Sulphur  dioxide,  in  pigments,  502, 
506. 

Sulphur   in   calorimeter  washings. 

Sulphur  in  cast  iron,  no. 
Sulphur  in  cement,  239. 
vSulphur  in  coal,  4,  52. 
Sulphur  in   coke,   55. 
Sulphur  in  dynamite,   731. 
Sulphur  in  fuel  oil,  462. 
Sulphur  in  oil,  474. 
Sulphur  in  pyrites,   78. 
Sulphur  in  slag,  88. 
Sulphur    in    steel,    144. 
Sulphur  test  for  oils,  399. 


Sulphuric  acid  method  for  silicon 

in  steel,   147. 
Sulphuric    anhydride    in    cement, 

198,  239. 
Sulphuric  anhydride  in  clay,  252. 
Sulphuric  anhydride  in  fire  sand, 

252. 
Sulphuric  anhydride  in  iron  ores, 

72. 
Sulphuric     anhydride     in     kaolin, 

^52. 
Sulphuric  anhydride  in  limestone, 

66. 
Sulphuric  anhydride  in  stone,  252. 
Sun  valve,  687. 


Tagliabue,    flash    and    fire    tester, 

445- 

Tagliabue  freezing  apparatus,  258. 

Tagliabue  viscosimeter,   381. 

Tailings,  in  road  material,  272. 

Talcose,  521. 

Tar  acids  in  creosote  oil,  356. 

Tar,   breaking  point,  352. 

Tar,  melting  point,  350. 

Tar  pitches,  339. 

Tarry  matter  in  petroleum  prod- 
ucts, 405. 

Tar,  specific  gravity,  350. 

Tars,  339. 

Tar  testing,  349. 

Tearing  length  of  paper,   561. 

Tempered  lead,  170. 

Tensile  strength,  cement,  219,  233. 

Terra  alba,  analysis,  510. 

Testing    cement,    methods,    207. 

Testing  concrete,  methods,  242. 

Testing  oil,  tar  and  pitch,  349. 

Thermometer,   Beckman,   28. 

Thermometer,  Heraeus  quartz 
glass,   719. 

Thickness   of   paper,   556,   567. 

Thorium  oxide,  in  Welsbach 
mantles,  730. 

Timber,  for  wood  block  pave- 
ment, 360. 

Time  of  setting,  cement,  215,  231. 

Tin  in  alloys,  167. 

Tin  in  brass  or  bronze,  161,  181. 

Tin  in  tin  plate,  155. 

Tin  plate  analysis,  153. 

Tin   plate,    composition,    154. 

Tin  plate,  sampling,  154. 

Tin  plate,   specifications,    159. 


INDEX 


759 


Tinting  test,  519. 

Titanic  acid  in  cement,  200. 

Titanic    oxide    in    clay,    fire    sand 

and  stone,  252. 
Titanium  in  iron  ore,  76. 
Tobin  bronze,  165. 
Toilet  soaps,  475. 
Total  solids,  in  water,  583,  596. 
Toughness  test,  for  macadam,  269. 
Transformer   oils,   428. 
Trap  rock,  crushing  strength,  254. 
Trolley  wheel  bronze,  169. 
True  red  lead,  in  pigments,  516. 
Turbine  oils,  427. 
Turbine  wheel  mixtures,   167. 
Turpentine,  analysis,  538. 
Turpentine,   specifications,   540. 
Tuscan  red,  496. 
Tutwiler    and    Bond    hygrometer, 

659. 
Type  metal,  165. 


Ultimate  analysis  of  oils,  472, 

Ultramarine,  497,  531. 

Umbers,  496. 

Union  Pacific  R.  R.  Report  on 
water   supply,   611. 

United  Gas  Improvement  Com- 
pany, analysis  illuminating 
gas,  655. 

United  Gas  Improvement  Com- 
pany, candle-power  computer, 
718. 

Lnited  Gas  Improvement  Com- 
pany, standard  bar  photom- 
eter, 716. 

U.  S.  Steel  Corporation  method 
of  sampling,  83. 

Unsaponified  matter  in  soap,  479. 


Van  Dyke  brown,  496. 

Vanier  combustion  train  for  steel 

analysis,  133. 
Vanier  potash  bulb,  472. 
Variation  in  coal  analysis  due  to 

size,   16. 
Varnish  analysis,  337. 
Vegetable  black,  497. 
Vegetable  oils,  453. 
Vehicle  in  mixed  paints,  535. 
Vermillion,  496,  533. 


Viscat  apparatus  for  cement  con- 
sistency, 213. 

Victor  metal,  169. 

Viscosimeter,  Doolittle,  378. 

Viscosimeter,  Engler,  299,  372, 
462. 

Viscosimeter,  Redwood,  380. 

Viscosimeter,  Saybolt,  374. 

Viscosimeter,  Tagliabue,  376. 

Viscosity  of  oils,  372,  423,  462. 

Volatile  and  combustible  matter 
in  coal,  i,  51. 

Volatile  matter  in  coal,  alternate 
method,  14, 

Volatile  matter  in  coal,  muffle 
method,  14. 

Volatile  matter  in  coke,  54. 

Volatile  matter  in  pigment,  523. 

Volatilization    test,    asphalt,    283, 

309,  345. 

Volatilization  test,  asphaltic  ce- 
rnent,  347. 

Volatilization  test,  asphalt  re- 
siduum, 346. 

Volumetric  method  for  nickel  in 
steel,  149. 

W 

Water,  acid  in,  579. 

Water  analysis  certificate,  599. 

Water  analysis  for  scale  forming 
ingredients,  570. 

Water,  bacteriological  examina- 
tion, 600. 

Water,    boiler,    complete   analysis, 

576- 
Water,  boiler,  rapid  analysis,  582. 
Water,    boiler,     sample    analyses, 

581. 
Water,  color,  598. 
Water  extract,  in  pigments,  523. 
Water  feed  generators,  679. 
Water,   filtration,   573,   599,  600. 
Water  for  locomotives,  606. 
Water  gas  manufacture,  670. 
Water  gas  tars,  339. 
Water,  hardness,  584. 
Water  in  gypsum,  511. 
Water  in  iron  ores,  74, 
Water  in  mortars,  214. 
Water  in  pigment,   522,  523. 
Water  in  soap,  476,  479. 
Water   of   hydration  in   clay,   fire 

sand  and  stone,  253. 
Water,  sanitary  analysis,  588. 


760 


INDEX 


Water  test  for  oils,  400. 

Wearing  surface,  asphalt,  342. 

Weight  of  paper,  556,  567. 

Welding,  oxy-acetylene,  689. 

Welsbach    mantles,    analysis,    730. 

Welsh  coal,  composition,  17. 

Wendler  apparatus  for  paper  test- 
ing, 557. 

White  brass,   170. 

White  lead,  496. 

White  lead,  analysis,  497. 

White  lead,  specifications,  518. 

White  metal,    165. 

White  metal,   analysis,   172. 

White  metal,  specifications,  189. 

White  pigments,  497. 

White  pigment,  analysis,  499. 

White  zinc,  specifications,  528. 

Whiting,  497,   509. 

Wijs  solution,  542. 

Williams-Westphal   balance,   366. 

Wilson  colorimeter,  453. 

Wire,  firing,  28. 

Wisconsin  flash  and  fire  tester, 
443. 

Witherite,  513. 

Wolff's  calorimeter,  592. 

Wood  block  pavement  specifica- 
tions, 358. 

Wood  fiber  in  paper,  546. 

Wood  pulp,  in  dynamite,   731. 

Wool  grease,  408. 


Wright    and    Thompson,    scheme 
for  soap  analysis,  478. 


Yellow  ochre,  497. 
Yellow  pigment,  497. 
Yttrium      oxide,      in 
mantles,  730. 


Welsbach 


Zinc  analysis,  93. 

Zinc  chrome,  497. 

Zinc  in  brass  or  bronze,  161,  183. 

Zinc  in  ores,  94. 

Zinc,  in  pigments,  504,  507,  508. 

516,  518. 
Zinc,  in  pyrites,  78. 
Zinc-lead,  506. 
Zinc-lead  white,  520. 
Zinc  oxide,  520, 
Zinc    oxide    in    cylinder    deposits 

728. 
Zinc  oxide  in  Paris  green,  495. 
Zinc  oxide  in  pigments,   508. 
Zinc  sulphate  in  pigments,  504. 
Zinc  sulphide,  white,  496. 
Zinc    sulphide,    in    pigments,    507, 

508. 
Zinc  white,  496. 
Zinc  white,   analysis,    506. 
Zirconium     oxide,     in     Welsbach 

lamps,  730. 


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